so my friend can get his hands on one for 200 american dollars.
does anyone know anything about this amp?
most importantly is it loud enough to practice with a live band?

i use a peavey classic 30 and we have a drumset.
would this amp keep the bass up with us?

right now he uses a 40 watt washburn amp and it is barely audible.
would this amp be a good buy?

It would probably keep up with the guitar, but I don't know if it would keep up with the drummer. 100 watts RMS from a solid-state bass amplifier is not the same as 100 watts RMS from a guitar amplifier.

The Crate BX series were decent practice amplifiers, but they weren't known for being especially rugged. They are two-channel amplifiers, and I have heard of plenty of problems with the channel selector switch failing. I would look for something better, with at least 200 watts if you want to use it with a band. That will give you the headroom you need without overloading the speaker(s). On the used market, you can do better for US$200.00.