i'm getting an used iphone 2g for a very very low price.. unlocked jail-broken.. is it safe to get one now the battery must have worn out.. passed its charge cycle etc.. how much will it cost me to get a new battery for it? and I've heard you cant plug in normal 3.5mm headphone jacks... i have a some really good creative headsets which i want to use on it 
(i want a used 2g cuz its cheap, i don't give a crap about 3g and ios 4.0)
(i want a used 2g cuz its cheap, i don't give a crap about 3g and ios 4.0)