I'm running a lemmy instance and using about 700mb, up from 500mb before I had any users (though I have maybe a dozen active users lmao)

But I'm not using much CPU at all though. 5% average on a 2core VPS VM. 4 gigs as well. I can scale up a bit and still afford it personally. After that Ill have to ask for donations, and if not enough stop registration.