Ok under $500 for a good bass head.
I'd go straight to the used market looking for an Aguilar TH350 (sold mine last week for ~$400) or Genz Benz Shuttle 3.0 ($300 to $350). I'm seeing GB shuttle amps on eBay for good prices these days with Fender apparently putting Genz Benz on hold.
I assume for church you don't need huge volume level so a couple hundred watts into a 2x10 or so would be more than enough.
Really, an Ampeg BA-115 may be all the bass amp you need, though the separate head would be nice.
Now, the BX500 is about $100 more than the BX250, but Carvin sometimes sells them on eBay with no tube (http://www.ebay.com/itm/CARVIN-BX500...item232f1577bc
) for $350. The BX500 has the advantage of having Speak-on outputs and can drive a 2 ohm load. The build-in graphic EQ is useless as is the tube preamp. On the down side, the BX500 has a cooling fan which can be heard. It is not loud, by any stretch of the imagination, and even in a small room probably would not interrupt anything, but it is there, and it does make sound. The BX250 with no fan is absolutely slilent. No way it will interrupt prayer time.
Oh, one more thing. The BX250 has a pre/post switch for the XLR DI. The BX500 does not. I don't recall if it is pre (probably what you want) or post (yuck) only.
- Keith -