Go thru this FAQ: How to use BlackBerry on Generic Data Plan - BlackBerryFAQ
Basically, any proxy-less data plan works fine unless you require push email. I am not very familiar with Bold but something similar to Curve must exist in Bold too. If it was a curve and I had a generic data plan I would do this..
Now here you may have to try a variety of options to have the thing work... possible values for APN:- (Try them in the sequence listed)
After each change you may have to Soft Reset your Bold.