It'll probably wind up cheaper than local if you get in on one of the stewmac (steward macdonald parts suppliers) orders that people on this forum periodically do. I ordered my B7 from them along with some other parts.
You may be interested to know that you can get cheaper cast versions:
http://www.stewmac.com/shop/Bridges,_tailpieces/Electric_guitar_tremolos/Bigsby_Vibrato_Tailpieces/Bigsby_B50_Vibrato.html
What are you putting it on?