Anybody here know anything about the....

ukulele? I can't seem to keep mine in tune, and when it does say its in tune the strings are unually loose. And when I go to tighten the strings, the tuner keys aren't stiff, they move back.....like what a piece.....Please help.....I think i probably need new tuners, but I already paid to much for this thing. Anybody out there who has got some words of wisdome for me?