I'm not familiar with BG Micro (yet), but I know
Unicorn has a hefty
minimum, which Jameco does not (while you're there, though, you might as
well pick up the socket as well and maybe some spare parts (like more
6502s).
Not long ago, Jameco had commodore PLAs for a song (something like a
dollar or less). I know a brazilian that bought 50 :o)
But remembering - You can put a 27C512 EPROM with a special bin in place
of a PLA! Google is your (best) friend! :D