My son (16) plays bass in a band that plays gigs in a youth center, a converted restaurant and some outdoor venues. I was wondering what size bass amp I need to get him? We don't have a lot of money to spend on this. I would like to limit it to $400. I know that is paltry, but I am currently not working and my husband will even balk at this amount.I just feel he needs to have the right equipment if we can get it. He plays an Excel 4 string and an OLP 5 string. They play metal. Thanks.