When you see fractions in the number of baths. you have to think about it this way: Each component of a bath room is a quarter (1/4 in fraction, .25 in decimal), the components are toilet, sink, shower and tub and they are normally in that priority order. Half a bath would be toilet and sink, add a shower and you have 3/4 bath, continue to add a tub and you will have a full bath. A 2.5 baths home will likely have 2 baths with all four components and a third bath with a toilet and sink.
The term reasonable bidding is a bit harder to define, and there are 2 basic possible types of bidding, a normal sale with multiple offers (or just 2 competing offers trying to outbid each other) and a bid at an auction sale in which all buyers assist to a place to make their offers, these offers are normally subject to certain regulations and minimum increments on the bids. the term reasonable is the hard part to define because is subject to the bidder judgement and in the current (seller's) market, depending on the area where the home is located, the competition might be fierce and in some cases higher than market value. You might need to get help from a Realtor to determine a fair market value for a property you might want to place your bid for. Good luck!!