To me, the price is worth it. I would never accept any less than that for my 74. (I would actually ask for more lol)
Looks real clean and thought was put into it. Even has a good looking rear filler panel
Heres a website that shows values for Novas with different options. I plugged in the fact that this Nova (the one you show in your link) has a 400 engine and high retail is $16K with average retail being a little over $8K
My Nova's high retail is just over $21K (as per how i built it) and the average is over $11K.
The 73-74's don't ever get much love
in the end, the value is depicted by ones love for the car.
Heres the website to run your Nova's value. Just change the parameters.