FHA guidelines will allow the seller to pay up to 6% of the contract price toward purchasers closing costs, pre-paids and discount points.

Conventional guidelines will allow the seller to pay up to 3% of the contract price toward purchasers closing costs, pre-paids and discount points.

This is very important for the first time homebuyer purchasing homes below $150k.  I recently had a client approved for FHA financing but the property was not FHA approved.  Client had enough money to put a 5% down-payment and qualified for conventional, except...the seller could now only pay 3% of closing which left a shortfall of about $1800. 

The $1800 left over closing costs added to the 1.5% more in down-payment killed the purchase.