I recently picked up a used BDI21 for £14.99 from Crack Converters in Redcar. They had quite a few useful/interesting/unusual bits of musical equipment in there, and a better range of amplification than most small music shops!
I knew these had a good reputation, but I am unfeasibly chuffed with mine. I really like the way the sound thickens up as you raise the Drive control, without going into audible distortion until the last 1/4 turn. Some forum posts knock it for lacking mids, but to me it still gives a fatter sound than straight DI. I bought it mainly for home recording - until now my best recorded bass sounds have come form the transformer-balanced DI output of my Demeter head, but that normally lives in my gig gear cupboard downstairs, so it is not that handy when late-night recording inspiration strikes. I have yet to record with the BDI21, but I think this is going to be a winner.