s/b = starting bid, aka starting price for the item c/o = current offer, how much has currently been bid on the item I assume you mean a/w instead of a/b, it means auto win, or how much you need to pay to straight up buy the item instead of waiting for the bidding time to end
You can also check this guide made by Plenty for the common abbreviations used in Royals http://royals.ms/forum/threads/common-mapleroyals-abbreviations.25086/