Oof. Not actually the end of the world for me but i do have two of their free instances that i rely on every day. Lucky for me i mostly just use the functionally unlimited bandwidth they give out for free (VPN to my home server so i can access Plex, Nextcloud etc via my domain name--basically zero CPU, but lots of big file transfers)
My god though, OCI is an absolute shambles, far and away the most awful cloud related UI of any variety I've ever used. Early on i didn't realize just how impossible it was to provision free resources, i got really lucky (probably helps i signed up in the middle of the night? Idk) but i deleted a misconfigured instance that i couldn't figure out how to fix... Took me a couple days to claim another.
They say they don't take prepaid or virtual cards but pretty sure they accepted my Privacy.com virtual card which i retroactively set a $1 spending limit on. I'll still have to go make sure they're not gonna try and charge me though. Can't trust em one bit (except with my VPN traffic lmao)