There is actually a generous free tier:
- first, you just have to tell me the pubkey you'll be using for signing the requests and I'll get you 10k credits on the house
- secondly, you can use the pubkey of the user to sign requests, and if they are minimally reputable they'll get automatically 100 credits every day. To give contex, that amounts to +100k users, and with 100 credits they'll be able to search for many hours most likely.