First of all, looks like you scored a good specimen, rust free, perfectly paintable. It is manual excelnt. About price, two things.
one*
There is a price list which tells about prices of older cars in several conditions, pristine, good, , moving and bad.
Second*
If you like Datsun cars, then, do not worry about the price, appreciate what you have and enjoy it. You can turn your B210 into a stock car, a street road racy daily driver,a pro racer(road or rallye/off road),it is up to your particular tastes.
I hope you like Datsun cars, if buying it for business(buy/sell) without any Datsun interest, I would recomend you selling it to a Datsun fan and look for more commercial vehicles(plastic hondas and the like)
Later.