Action figure prices?

i am going to a convention in august and i will be selling my action figures. any suggestions on what i should sell them for? i have figures from the first x-men movie, 1st spider-man movie, 1st scorpion king movie, 1st planet of the apes (mark whalberg) movie, lord of the rings movies, xena, tarzan the epic adventures, hercules (kevin sorbo). please advise, thank you!