'04 Aveo Hatch - blown head gasket - drive until it dies or sell now?

[Rob D]

My sister bought an '04 Hatchback for $300 with 120k miles from a friend. Spent another $600 or so to get a couple tires, new windshield and work (unsure what) to get it through yearly state inspection in Virginia (it passed). Check engine light came on and her mechanic says the car has a blown head gasket. She has very limited funds and cannot afford the heavy repair cost. Should she sell it now (with full disclosure) and try to get her money back out of it or drive it until it completely dies and then sell it? I'm thinking sell now.