I’ve been bidding on and following Namecheap expiry auctions for .AI and .IO domain names. Most auctions have a standard starting bid of $15 plus the renewal fee. There are some that have $5 or $10 minimum bids, but most seem to be $15.
One thing I noticed is that some auctions have a starting bid of $400 with standard renewal prices. I believe these higher bid amounts are set by the registry operator, Identity Digital, and they impact certain names the registry identifies as “premium,” or some other designation they choose.