That's amazing! I've seen mass market crap offered for next to nothing, given away or take a trip to the dumpster, but never any Bryston components.
The 2B-LP has been in production for awhile and I'm not sure of the vintage of yours, but they sell new for $2150 in the US and there are a few listed on eBay asking $450 to $750.
Don't remember seeing a listing for a BP4, but it's hard to imagine it wouldn't be worth at least $300 in working condition.
Steve