Don't even try playing through a guitar amp unless you want to buy a new guitar amp A.S.A.P. If you want to play Bass get Bass gear.Every musician is on a budget but don't sacrifice sound with junk.The second part you mention is playing with a drummer. Well here is my outlook. Even if a drummer is dampening his kit a 50 watt bass amp will have to be turn up full in order to hear. Now along with drums you have 1 or 2 guitar players and vocals. You will need at least 150 watts to hear yourself clearly with good sound. I reherse with a 300 watt head & cab and with 2 guitar players and vocals it usually is turn about 1/2 way, perfect sound without any distortion at all. The best way to judge what size of amp is needed double what your guitar players are using. if they use 75 watt amps your bass should be 150 watts. If money is a object try renting amps. if it is for you to practice on buy a 20 watt practice amp. hope this helps it is just my opinion.