Github pages if it's static enough, or for any static part.
If the amount of data is small / static-ish, and can/needs to be changed by non-tech people, I've also used Google spreadsheet. Example: https://hasgluten.com
The only thing I haven't accounted for here is if you're querying against some sort of database, which would incur additional hosting costs.
Which is basically AWS lambda / gateway with minimal setup and extremely cheap.