Joe, it depends on whether you are talking about live foreclosure auctions at the property, or online auctions for REO property. (These are generally bank owned properties that have been foreclosed already)
1. Live foreclosure auctions: most live auction investors learn to do their own title searches online prior to showing up at the auction. Then once you win the bid, you can pay for a title search. If you find something that you believe can't be fixed with a limited outlay of funds, you will lose your deposit, which is frequently 5-10K. Bear in mind that foreclosure auctions are among the riskiest of acquisition strategies, and should probably not be on your list of methods until you are more experienced. For example, you can end up winning the bid on a second mortgage foreclosure, which means you will take title subject to the existing first position mortgage.
2. Online auctions: You will have to sign their contract, not your own, and it will generally specify insurable title, not marketable title. The difference can be huge. I wrote a blog post about the risks.
Since online auctions frequently now require deposits by credit card, you may be stuck with your deposit at risk if you win the bid and don't complete the transaction. But that may be preferable to taking title to a property with a huge problem. You will also have difficulty in obtaining funding on a property with a title issue. There are also title issues (such as missing bank assignments) that are relatively easily fixed.
Bottom line: either learn to do them yourself, or establish a relationship with a title company/abstractor that can run preliminary title for a fairly reasonable amount. Think of it as insurance on those properties you are serious about. Perhaps someone else will chime in with their method that will differ.