I use both without an account. Relay is down to checking /r/all in the evening for a little bit and even that is already apparently at 48 calls, meaning I had to pay 2 bucks for just that casual scrolling alone. lol

Infinity is good because you can create a home feed with subscribed subs without having an account. I use that for news and Ukraine related stuff, as well as the odd game related sub. I was thinking of doing the custom api key thing but that requires an account and is kind of a hassle. I also doubt they keep that open for too long.