How do you perform due diligence economically?

[Hen Ley]

I'm interested in bidding on a property scheduled to be auctioned.  Currently the private party still owns the property, so if there isn't a successful bidder it will revert to the bank.

What's the most economical way to do due diligence?  I got a complimentary property profile from the title company, however, a full report will cost $200.  The property is also tenant occupied with a seemingly nice person whom I think would be amenable to showing me the inside of the property, but I would feel obligated to offer a cash incentive for the inconvenience.  These figures aren't abysmal, but if you do this with every auction property it starts to add up, particularly if you're not leaving with the property.  Any suggestions as to how to be thorough in your due diligence while still giving consideration to expenses?