I have a realistic scenario: I write event (think food festival) software. 9-10 months out of the year there is almost zero traffic, 1-2 months have mild traff

I have a realistic scenario: I write event (think food festival) software. 9-10 months out of the year there is almost zero traffic, 1-2 months have mild traffic, ~2 weeks are higher traffic, and then 1-5 days (during the event) are very busy. I'd be hard pressed to find anything other than my current stack (Lambda/DynamoDB/S3/Route53/APIGateway) that costs as little. In the off-months my costs are ~$5 if that and in the month of the event that might get as high as $15-30. I cannot imagine being able to host it locally/colocated (for the month of the event) for that cheap and that doesn't even touch on the hardware cost (I'm thinking just electricity and co-locating costs). Yes, I'm a small fish and this is just my side business but for me the cloud is way cheaper. Anything with very spiky/uncertain load can be good candidate for the "cloud" but a big part (IMHO) of making the cloud work is using the managed services and using them smartly. If all you do is spin up EC2 instances then no, the cloud is probably not going to be cheaper in the long run.