Have they figured out how to make API Gateway not cost an arm and a leg yet? I absolutely adore Lambda for side projects, but every time I wire up API Gateway I'm worried I'm going to saddle myself with a huge bill.
You can also hook up an Application Load Balancer to Lambdas if that works for you: https://aws.amazon.com/elasticloadbalancing/pricing/
It still increases the cost of running Lambda a whole lot, but that seems pretty reasonable for the projects I'm running.
Looks like it costs $1 per 1 million HTTP calls. That does not sound very costly if you are talking about just side projects which may not generate close to a million requests?