Compute and storage are the numbers on the plan card. Outbound traffic, the data your server sends back to visitors, is the number that is usually somewhere else entirely, and it is the one that produces the surprise at the end of the month. For a workload that moves real volume, egress can quietly become the largest single item on the bill while the sticker price stays reassuringly small.
How egress is actually billed
Two things vary between providers, and both matter. The first is the included allowance: how much outbound traffic comes with the plan before metering starts. The second is the overage rate: what each additional gigabyte costs once you cross that line. A cheap-looking plan with a small allowance and a steep per-gigabyte rate can be far more expensive in practice than a dearer plan that includes generous traffic.
The hyperscaler model is the strict one. Across its services, AWS gives you the first 100 GB of data transfer out to the internet free each month, and after that it meters. On Lightsail, its own VPS product, the $5 instance bundles 2 TB of transfer and the $12 instance bundles 3 TB; go past the allowance and the overage is billed at $0.09 per GB. That per-gigabyte figure looks tiny until you multiply it by the volume a busy site or a media-heavy app actually pushes.
The number that surprises people
Here is the same workload priced two ways. Suppose an application serves 5 TB of downloads in a month, which is unremarkable for anything with video, images, installers or a public API. On the Lightsail $5 plan you are 3 TB over the 2 TB allowance, and 3,000 GB at $0.09 is $270 of overage. The server that advertised at $5 now costs about $275, and roughly 98 percent of that bill is traffic, not compute. Nothing was mispriced; the compute really is $5. The cost simply lives in a line most buyers never look at before they commit.
The lesson is not that AWS is uniquely expensive here; every metered provider works this way, and the trap is the same one across the market. It is that the plan price and the traffic price are two different questions, and only one of them is printed on the card you compare.
Where the model flips entirely
The contrast that makes egress worth understanding is object storage built for the web. Cloudflare R2 charges $0.015 per GB-month to store data and, deliberately, nothing at all for egress: its own pricing page describes it as object storage without egress fees. Backblaze B2 stores at $6.95 per TB per month and gives free egress up to three times your stored data each month, charging $0.01 per GB only beyond that. So the very same 5 TB of downloads that costs $270 in server overage costs $0 on R2, or about $20 on B2 if you are serving well past the free multiple.
That 90-fold-and-up spread is not a loophole. It reflects a real split in how providers treat bandwidth: some price it as a scarce metered resource attached to compute, others treat it as free because they make their money on storage and requests. The practical implication is that the cheapest place to run a server is often not the cheapest place to serve its files.
What to check before you commit
Three checks save the surprise. First, read the included allowance and the overage rate together, not the plan price alone; a plan with 20 TB included and a low overage can beat a "cheaper" plan many times over once traffic is real. Second, separate what actually needs to leave the server: static assets, downloads, images and video usually do not belong on a metered compute instance at all, and moving them to a zero-egress store or a CDN in front can collapse the traffic bill to near nothing. Third, estimate your monthly outbound volume honestly before choosing, because the difference between providers only shows up once you know the number you are multiplying.
If you want to compare plans on total cost rather than the showcase figure, the included traffic and overage terms sit alongside price in the catalog, and the way we weigh those items against each other is set out in the matching methodology. Egress is the line that most rewards checking before you sign, because unlike compute, it scales with your success.
The figures in this article are taken from the published pricing pages of the providers named: AWS EC2 and Lightsail pricing for the free tier, included transfer and $0.09/GB overage; Cloudflare's R2 product page for its storage rate and zero egress fees; and Backblaze's cloud-storage pricing for B2 storage and its egress allowance, all as listed in August 2026.