A good start is figuring out comps on regular ones, see if you find any anniversary ones to comp
And consider how much work your car needs without spending more than it's worth.
That's the basic process for any vehicle.
In my case, I bought a 7th gen for $800, all in all I've spent $1,200 to tow it home and replace all of the brake components, suspension, wheel bearings, and while it still needs a lot more work for having spent $2,000, I have a car I can probably sell for $3,000 as-is. A couple hundred more dollars and I can sell it for $4,000. Presently I am doing all my own repairs.
