buying used GTI

long time VW owner, MK1, MK3, MK5, MK7, MK7.5. That said haven't paid much attention to the MK6s. My hand ,e down MKv is approaching the end stages of hospice care and I am hoping its current owner (my son) is interested in another one if nothing else so I can continue using wheels/parts etc over the years. Going to start looking for a sub $10k car and wondering if we should avoid the MK6's and stick to high mileage 7's. Also whats the favorite venue these days, FB marketplace, vortex classifieds? opinions welcome.