Ways to earn 250$?

ok guys im tryying to earn 250 so i can get a b guitar and a b amp and i wanna sell my 15 watt amp my red fender squire but its missing a string and my greg bennet acoustic guitar idk i think thatll get me 120 but besides me selling them how much would i get and whats other ways to raise...and im 13 so like nothin to hard...