I had experience with a basement that had problems that were hidden behind wall and purchase was in the summer.

A rare gem of a class taught by a guy who advised Wall Street.  

What are some of the hidden costs associated with buying and flipping houses?

Access hidden notes in the MLS (as opposed to syndicate information from realtor.com or redfin.com)4.

There is no point putting it into the plan in the first place if your only intention is to pull it back out immediately in a loan.For someone who has had a 401k for some time and contributed over many years, this "hidden cost" of losing the deferral basis of the 401k funds is acceptable if the use of the borrowed funds will be of real benefit such as getting them started in real estate investing.  

My info is not hidden.

Ask for referrals.Personally, I don't think fees are as important because the lower cost guys typically either have hidden fees or provide poor property management that creates avoidable costs.

I'm not even considering bidding yet, because I have concerns about hidden expenses (past due: hoa fee's, taxes, liens, etc)I see lots of people saying to search the local county records, but perhaps my local county website is just "different".  

However, the plaintiff's max bid is hidden from view so I don't know what they are willing to bid up to until auction day.

Watch out for hidden costs.