Today I watched auctions and bid on auctions for mill accessories.

a) I bid $1250, the winner bid $1275
b) I bid $10, the winner bid $10.50
c) I bid $20, the winner bid $52
d) I bid $100, the winner bid $107
e) I bid $255, the winner bid $260
f) I bid $30, the winner bid $31
g) I bid $10, the winner bid $36
h) I bid $10, the winner bid $11
i) I bid $66, the looser bid $47.98, causing me to pay $48.99

In all 9 auctions, I was the first to bid, or bid several multiples of
the existing high bid.

Most watched auctions end without any bids.

So why in all cases does another bidder appear if I bid?

Could it be the seller has another identity to shill up the price?