What a deposit is for
An online bid costs nothing to place. Without a deposit, a house has no way to tell a serious buyer from somebody who will change their mind on Monday — and every lot that has to be re-run costs the seller a week and the house its credibility.
The deposit is usually a percentage of the price, due within a short window, and it is credited against your total. It is not a fee.
The window is short on purpose
Twenty-four to seventy-two hours is normal. The lot is held off the market during that time, so the house is carrying the risk of your silence. Wire transfers take a day to move and longer across a weekend — start on the day you win, not on the day it is due.
Send the receipt
A wire arrives under the name on the bank account, often with no reference to the vehicle. Emailing the transfer confirmation with the lot number is the single thing that most reliably prevents a paid deposit from being treated as missing while somebody reconciles the account.
When the deadline passes
Most houses release the lot back to the market and may offer it to the next bidder. Some charge a fee, some suspend the account, and all of them remember. If something goes wrong, say so before the deadline rather than after — a house that can plan around a delay will usually work with you.
From the auction floor
See how this works on a real lot.
Every listing carries its inspection report, its full specification and its bid history. Read one before you decide what it is worth to you.