They charge shipping on top of the winning bid price. I believe shipping is.. $7.99? Maybe 9.99? One of those two. You can choose a day to consolidate winnings into one weekly shipment if you like, so you will incur less individual shipping charges and may just have one slightly less expensive shipment.
That way if you regularly purchase deals you can find (more occasional than it seems on a lot of products there, factoring in tax and shipping. The rare great deal can be found, but don't let yourself fall into the trap that is auctions for what may be a very small savings.)
In case you weren't aware, CB is ran by Cigars International, and CAuctioneer is ran by Famous-Smoke. So keep an eye out there for better values.
A lot of times it may be better to save up and bundle purchases from the regular version of the said auction sites. That way you can find deals with free shipping to eliminate that extra cost, and still get a better value than a small discount through auction with a high shipping fee.
They automatically charge the card on file, you do not check out after "winning" the auction. Your winning high bid is your acceptance of the purchase.