Trading

This is a question more about this forum than the game, but I couldn't think where else to post it.

When people are selling stuff they sometimes have 2/3/4 prices, what do all these kind of things mean:

s/b 100k
b/o 50k

etc etc??

Side-bet? Buyout. OBO-or better offer.

starting bid = sb
buy out = bo
current offer = co

thanks for info