If you asked the wrong person whether buying a home with a child support lien is possible, s/he will tell you it's impossible. And s/he would be correct. Because after all, he doesn't know.
However, there is a way and it's as simple as instructing the closer to request from his/her underwriter a "waiver" of the lien or judgement.
In most cases, all that is required is that you have a payment agreement in place and payments have been made timely. Make a print out of the payments made and submit to the underwriter to waive the lien requirement. The title company will issue a title commitment to the bank or lender and approves for closing.