Hidden Cloud Costs: What AWS Doesn't Tell You About Data Transfer

You estimated your AWS bill at €500/month. The invoice arrives: €1,247. Sound familiar?

Welcome to the world of hidden cloud costs—the fees that don't appear in AWS marketing materials but show up every month on your bill. Data transfer charges, NAT Gateway fees, load balancer costs, and support tiers can easily double or triple your expected cloud spend.

In this guide, we'll expose every hidden cost in AWS, show you how to audit your bill, and explain how transparent pricing alternatives can eliminate surprise invoices forever.

The $10,000 Surprise Bill: A Real Story

A European SaaS startup reached out to us after receiving a shocking AWS bill. They were building a video processing platform and had budgeted €2,000/month for infrastructure based on EC2 and S3 pricing.

Their actual bill? €11,847.

The breakdown:

• EC2 instances: €1,850 (as expected)
• S3 storage: €340 (as expected)
• S3 data transfer out: €7,230 (not expected)
• NAT Gateway: €892 (not expected)
• CloudWatch: €435 (not expected)
• Other charges: €1,100 (not expected)

They had processed and served 80TB of video content to users. At €0.09/GB for data transfer, that alone cost €7,200.

This story isn't unique. Let's break down every hidden cost so you never experience this shock.

Hidden Cost #1: Data Transfer (Egress) Fees

This is the biggest surprise for most AWS users. Every byte of data that leaves AWS costs money.

AWS Data Transfer Pricing

What Counts as Egress?

Everything leaving AWS to the internet:

• API responses to your users
• Images and files served from S3
• Video streaming
• Database query results (if accessed from outside AWS)
• Backup downloads
• CI/CD artifacts

Real-World Examples

Hidden Cost #2: NAT Gateway

If your EC2 instances are in a private subnet (best practice for security) and need internet access, you need a NAT Gateway. And it's expensive.

NAT Gateway Pricing

• Hourly charge: €0.052/hour = €38/month per NAT Gateway
• Data processing: €0.052/GB processed

Why This Adds Up Fast

A typical production setup might have:

• 2 NAT Gateways (one per AZ for redundancy) = €76/month
• 500 GB/month of processed data = €26/month
• Total: €102/month just for NAT

Scale that to 5TB of processed data and you're at €336/month—for a service that's essentially routing traffic.

DanubeData Alternative

DanubeData VPS instances have direct internet access included. No NAT Gateway needed. No extra charges.

Hidden Cost #3: Cross-AZ Data Transfer

Using multiple Availability Zones for high availability? Great for reliability. Terrible for your wallet.

The Invisible Cost

AWS charges €0.01/GB for data transferred between AZs—in both directions. So when your app server in AZ-a queries your database in AZ-b:

• Request: €0.01/GB
• Response: €0.01/GB
• Total: €0.02/GB round-trip

Real Impact

A moderately active application might transfer 500GB/day between AZs:

• Daily: 500 GB × €0.02 = €10
• Monthly: €300
• Annual: €3,600

Most teams don't even know this charge exists until they audit their bill.

Hidden Cost #4: Elastic Load Balancer

Load balancers are essential for production applications. AWS makes you pay for the privilege.

Application Load Balancer (ALB) Pricing

• Hourly charge: €0.0252/hour = €18.40/month base
• LCU charge: €0.008/LCU-hour

What's an LCU?

LCU (Load Balancer Capacity Unit) is calculated from the maximum of:

• 25 new connections/second
• 3,000 active connections/minute
• 1 GB/hour for EC2 targets
• 1,000 rule evaluations/second

Typical Costs

Add a Network Load Balancer for TCP traffic? That's another €18.40/month + €0.006/NLCU-hour.

Hidden Cost #5: CloudWatch

Monitoring is essential. AWS knows this and charges accordingly.

CloudWatch Pricing Breakdown

• Custom metrics: €0.30/metric/month (first 10,000)
• Logs ingestion: €0.57/GB
• Logs storage: €0.03/GB/month
• Dashboard: €3/dashboard/month
• Alarms: €0.10/alarm/month (standard), €0.30 (high-res)

A Typical Production Setup

That's €1,188/year just to see what's happening in your infrastructure.

Hidden Cost #6: Support Tiers

Need help from AWS? That'll cost you.

The Support Tax

If your AWS bill is €5,000/month and you need Business support, that's an extra €150/month (3%)—€1,800/year for the privilege of talking to someone when things break.

Scale to €20,000/month and Business support costs €600/month—€7,200/year.

Hidden Cost #7: Elastic IP Addresses

Need a static IP? Free while attached to a running instance. But AWS charges for:

• Idle EIPs: €0.005/hour = €3.65/month per unused IP
• Additional EIPs per instance: €0.005/hour each

Forgot to release an EIP when you terminated an instance? That's €3.65/month until you notice.

Hidden Cost #8: EBS Snapshots and Storage

EBS snapshots seem cheap at €0.05/GB-month. But they accumulate:

• Daily snapshots of 100GB volume = 30 snapshots = ~3TB = €150/month
• Keep them for 90 days? That's potentially €450/month for one volume

Multiply by 10 instances and you're at €4,500/month in snapshot costs alone.

Hidden Cost #9: Secrets Manager

Storing secrets securely? Essential. AWS Secrets Manager pricing:

• €0.40/secret/month
• €0.05 per 10,000 API calls

100 secrets (database credentials, API keys, etc.) = €40/month = €480/year.

Hidden Cost #10: The Reserved Instance Trap

AWS promotes Reserved Instances as a way to save 30-60%. What they don't emphasize:

• 1-3 year commitment: Pay whether you use it or not
• Upfront payment: Best rates require full prepayment
• Instance type lock-in: Can't easily change sizes
• Region lock: Reserved capacity doesn't transfer
• Capacity planning required: Guess wrong, pay anyway

Many companies end up with unused reserved capacity costing thousands per month.

Auditing Your AWS Bill: A Step-by-Step Guide

Here's how to find hidden costs in your current AWS bill:

Step 1: Enable Cost Explorer

# AWS Console → Cost Management → Cost Explorer
# Enable detailed billing reports
# Set up cost allocation tags

Step 2: Check Top Cost Drivers

# AWS CLI
aws ce get-cost-and-usage 
  --time-period Start=2025-01-01,End=2025-01-31 
  --granularity MONTHLY 
  --metrics "BlendedCost" 
  --group-by Type=DIMENSION,Key=SERVICE

Step 3: Identify Data Transfer

# Filter for data transfer costs specifically
aws ce get-cost-and-usage 
  --time-period Start=2025-01-01,End=2025-01-31 
  --granularity DAILY 
  --filter '{"Dimensions":{"Key":"USAGE_TYPE_GROUP","Values":["EC2: Data Transfer - Internet (Out)","EC2: Data Transfer - Region to Region (Out)"]}}' 
  --metrics "BlendedCost" "UsageQuantity"

Step 4: Check for Idle Resources

Look for:

• Unattached EBS volumes
• Idle Elastic IPs
• Unused NAT Gateways
• Empty S3 buckets with lifecycle costs
• Stopped instances still incurring EBS charges

Step 5: Review Support Costs

Check your support tier. Many teams are on Business support without realizing the 3% tax on all spend.

The DanubeData Difference: Transparent Pricing

At DanubeData, we believe in pricing that doesn't require a calculator or surprise you at month-end.

What You Pay Is What You See

No Hidden Fees

✅ No egress surprises
✅ No NAT Gateway charges
✅ No cross-zone transfer fees
✅ No support tier upsells
✅ No snapshot storage gotchas
✅ No load balancer LCU complexity

Simple Monthly Bill

# Typical DanubeData invoice:
VPS Medium:         €17.99
PostgreSQL Medium:  €39.99
Redis Small:        €9.99
Storage:            €3.99
------------------------
Total:              €71.96

# No surprises. No fine print.

Cost Comparison: Same Workload, Different Bills

Let's compare the real cost of a typical production workload:

Workload: Web application with API, database, caching, and file storage. 1TB egress/month.

How to Migrate Away from Hidden Costs

Ready to escape the AWS cost trap? Here's your migration plan:

Week 1: Audit and Plan

1. Download detailed AWS billing reports
2. Identify all hidden costs using the steps above
3. Map your current infrastructure to DanubeData equivalents
4. Calculate expected savings

Week 2: Set Up and Test

1. Create DanubeData account
2. Provision equivalent infrastructure
3. Deploy your application to staging
4. Run load tests to verify performance

Week 3: Migrate Data

1. Set up database replication or dump/restore
2. Sync object storage
3. Update DNS with low TTL
4. Test thoroughly

Week 4: Cut Over

1. Final data sync
2. Switch DNS
3. Monitor closely
4. Terminate AWS resources
5. Celebrate your savings

Conclusion: Don't Pay the Cloud Tax

AWS built an incredible cloud platform. They also built an incredibly complex pricing model designed to extract maximum revenue. Hidden costs like egress fees, NAT Gateway charges, and support tiers can easily double your expected bill.

You don't have to accept this.

DanubeData offers:

• ✅ Transparent pricing—no hidden fees
• ✅ Generous traffic included—no egress surprises
• ✅ Free support—no 3% tax
• ✅ European hosting—GDPR compliant by design
• ✅ Managed services—databases, caching, storage

👉 Calculate your savings with our pricing calculator.

Or create a free account and see the difference yourself. Deploy a database in under 60 seconds—no credit card required for testing.

Have questions about hidden costs or need help auditing your AWS bill? Contact our team for a free infrastructure review.