Wire transfers are generally the lowest fee way to pay for the cars. Some of the brokers and auction houses accept credit cards, but watch out for 'convenience fees' for using them.
Wire Transfer
If you're anything like the author, you've heard of wire transfers you're whole life but may never actually have used one. It is not free, and it is a hassle event with a great bank.
Similar to the previous steps, IAA and Copart are setup to deal primarily with other companies on a massive scale. They generally delegate the responsibility of getting them paid to you, the individual buyer. What this means is you need to decipher the wire transfer instructions yourself and then shepherd the process through. This is not without risk as they have post-sale storage fees if there is a delay in receiving your payment.
Here's a specific example of the wire transfer instructions for the 
2005 BMW 545i.
- Download the wire transfer instructions from the auction house.
- Request a wire transfer from your bank. Suprisingly, this is a multi-step process and you'll need to request it, then wait for it to go through, possibly with a phone call for verification.
- Fill out the wire transfer form with the correct information. The first image below is the IAAI instructions filled out. The second two images are the receipt from the bank with the wire transfer information.
- Send the above documents to the auction house, in this case buyerpayment@iaai.com. Wait for the auction house to confirm the payment.
- Wait for the auction house to release the vehicle.
Credit Card
Copart and some brokers also accept credit cards. They mitigate their exposure by chargin convenience fees, membership upgrade fees and deposits. These are covered in detail with real world examples in the Step 4 - Define Your Budget section.
You're almost there. At this point you've paid for the car, read on to know what to expect at the delivery phase.