AWS is pretty generous on giving credits to startups, to help them cover the AWS bills in their early days (well you know so that they can grow deeply within AWS platform, and eventually AWS will get you to pay the bill with real money). This program is called AWS Activate, you can find a lot to read on https://aws.amazon.com/activate/, but there is something AWS are not telling you.
1. You can’t use credits on certain things
Go to your AWS billing dashboard -> Credits -> Complete list, you will see a list of services the credits cover, the list is pretty comprehensive, but it doesn’t cover everything, always make sure to have a look at this list before you make a decision.
2. You can’t use credits purchasing reserved instances
Well, you are right, it’s more or less the same as 1. You can’t use credits on certain things, but I list it as a separate point for a reason, a lesson was learned, that was I thought “Ah let me use the credits to buy some 36 months All Upfront RI so that I can use the credits paying for future bills even after credits expire”. How smart! Huh? Why ~1k is gone from my credit card?! After chatting with AWS support, it turns out that AWS credits don’t cover All Upfront RI purchase. But, you can still use the credits for the ongoing fee for No Upfront or Partial Upfront RI.
Tip. AWS support is pretty flexible, they refunded the money, so just submit a support ticket if you have any requests.
3. Do not overspend your credits
Human nature, when you have a billion you wouldn’t even blink when you buy a Porsche. When you have lots of AWS credits to burn people turn to not care about cost optimization, but credits don’t last forever, when it expires the bills will eat your profit like a monster, and you can’t do too much because it’s not easy to optimize your infrastructure from a cost-saving perspective. Always use your credits like they don’t exist!