1966 Valiant Value
In good running condition around $2,000 with some minor issues to sort out. It depends on condition and some other factors. Maybe some more if its in exceptionally good original condition or has a V8 & AC. But maybe less than that too. To me “new” tires means tire with a date code of 2019, not looks new - today’s tires should be replaced after five years and many vintage cars don’t get driven a lot and the tires look great but are old and should be replaced. Some pics would help a lot with understanding “rust spots”.
The person selling most likely is expecting to get all of their investment back and this never happens with Valiants.
The market value of this car may be much lower than the value to you. With more info & pics we can help with a fair market value but you need to determine the value to you.