Not bad!
- The ball perfectly fits inside the basketball ring
For this sentence you would probably want to put “perfectly” after “fits”, so “The ball fits perfectly inside the basketball hoop.” (Oh yeah, we also say basketball hoop rather than ring.)
- (To Fit) as a satisfaction: my monthly payment completely fits my needs cause i can buy all what i want
For this, you would probably want to put “completely” after “needs” and say “because” rather than “cause.” “Cause” is more of a spoken, not written, shortening of “because.” Here you need the full word. There are a couple other corrections that you’ll notice below.
So “My monthly payment fits my needs completely because I can buy everything that I want.”
But not bad at all, well done!