While your parents are able to sell you their home for a lower price than market value, that discount may be subject to the estate and gift tax depending on the amount and their lifetime giving habits. As of 2019, you and your spouse can each gift $15,000 to an individual annually without paying a gift tax, as long as you don't exceed your unified federal gift and estate tax exemption of $11.4 million total over your lifetime ($22.8 million between the two of you.) So, if your parents sell their home to you for $30,000 under its value, you're in the clear. If the discount is over this amount, but your parents have not made substantial donations over their lifetimes, the gift also will not be subject to the gift tax.