when buying a house that is in foreclosure what payments are involved ?

Much like Cheryl mentioned, many of the fees and expenses are the same as with a traditional sale.  Keep in mind, with an REO property, you have a greater risk of an appraisal not being within the guidelines of your loan(so kiss the money goodbye for that), spending your money on inspections (that you will not get back), etc.  

Some of the Sellers are trying to charge buyers fees, such as an admin fee or for processing.  If working with the right agent, many times this can be removed.  I have seen these fees from a few hundred dollars to almost as high as $500.

There is almost always a per diem if you do not settle per the designated date as stated in the contract of sale.  Typically, anywhere from $50-150 per day.

With an REO property, a Seller will want you to use their closing attorney/ entity.  If you do, they usually will give you a discounted rate on something (or the closing attorney will).  If you do not opt to use this preferred closer, you will likely have a few extra additional fees having two closing parties handling the transaction.  Your Contract of Sale will outline this.  

Lastly, almost everything is negotiable.  Keep in mind, you don't have as much leverage when you are financing a home, such as with an FHA or VA loan.  CAUTION- people are misled to believe they can get steals on REO's.  Yes, when you are paying cash and can settle quickly, with as little hassle to the seller.  You get discounted prices on REO's with a loan, just not as deep of a discount, typically as you would as a cash buyer.
  
Oh, I should mention.  Not necessarily a fee or up front payment to think about is the "what if" factor.  Often traditional home buyers may opt for a short sale or REO.  There is ALWAYS something wrong with the property which was not disclosed or found on your inspection.  Usually, they are big ticket items.  I would factor in an additional 10-15% just for the "what if".  This will occur AFTER you settle.***Your agent is not to blame for the unforeseen repairs.  The home inspector is not to blame either.  Neither is your lender or the appraiser.  None of them have a crystal ball.  You are purchasing REO and short sale properties as-is. You will sign tons of paperwork acknowledging this.  

I know I may sound like a ray of sunshine.  A majority of my transactions come from distressed property sales.  It is better to go in knowing this than to be surprised after you have closed.

Best of luck.

The best way to know for sure would be to get with a lender. They can tell you what will be required in purchasing a foreclosure. The fees are usually the same as they would be in a resale home. Most every foreclosure is sold "as is" so that's something you really need to read up on. Since they are "as is" in many cases the homes won't pass the appraisal process on many loans. So be certain to talk with your trusted lender to understand the ins and outs of buying one of these homes. Thank you for your question.