Ok so i am having no luck at doing this can you help?

I am going to an airsoft war with a couple friends and i would like to know where i can find a pistol or sub machine gun for as low as 15 dollars or less BUT it must use a battery OR a CO2 canister. not including the bb's or co2 so any ideas on where i can find one ONLINE as well. I would greatly appreciate your help if anybody can spot me on this. 10 points to best answer. OOHHH and MUST be FREE SHIPPING!!!