Just for playing my bass in my room.
Are you in the USA? The Acoustic B30 is a decent and cheap amp for practicing at home. Much less than $300, I paid $60 for mine used. It has a headphone jack and an 'aux input' for playing along to CDs or MP3s. I like the Acoustic because it has a 12" speaker which I think sounds beefier than the typical 10" or puny 8" speakers that come on some bass practice amps. Having said that, a lot of people like the Ampeg practice amps.
20 or 30 watts is plenty for practicing at home. 50 watts isn't needed for home practice, but is nowhere near loud enough for (most) band use; in my opinion there's no point point in buying any bass amp with more than 30 but less than 200 watts unless you play a 'quiet' form of music like jazz or bluegrass.