If you are a multiple car business like a:
car rental service
You can obtain auction access and avoid the dealer markup by obtaining your dealer license.
If you are buying more than three vehicles a year you may find it to be a very good move to get your dealer license and benefit from lower car prices, better cars to choose from and ease of transactions.
And becoming a dealer also allows you better resale prices at disposal.
So why not, – buy at wholesale – sell at retail – and use the vehicles in you own business.