None of the auctions are open for bidding - you are just looking at the start price.

Those are just the starting bids. Bidding doesn't open until mid January, I think.

The opening bids on auctions are almost always meaningless and set very low - the auction company knows that the valuable items will be bid up fast enough, and they do NOT want anything left over because then they have to dispose of it.

Why some are 25 and some are 50 I'm not sure; they may raise the bid a bit on items they think might not get many bids.