i just bought my first ever guitar. its a cheap one. got it for ~$80

i am new and have no idea how it works. where can i find very basic guide online?

Just start by learning a few basic open chords - A, E and D. There should be plenty of info re them free on the net. Also it is tricky sifting through the junk but there are some quality free lessons on youtube.
Learn some easy songs, learn the theory behind them, practice like crazy.

Gibson 2005 Les Paul Standard
Fender Road Worn Strat w/ Noiseless pickups
Marshall JCM 2000 401C
Marshall Vintage Modern 2266
Marshall 1960A cab (Dave Hill from Slade's old cab)
Ibanez TS9DX
EHX Little Big Muff
Freshman Acoustic
the first thing I learned on the guitar was some easy Whitestripes stuff. worked out great and now im at complex fingerpicking songs.