They're fairly plentiful on eBay and seem to go for $50-$100 for the base 327 type pump in need of a rebuild. Pulley and brackets will increase it to the $150 you mentioned. The L30/L48 pumps are a little more difficult to find and command a little more $$. If the car had AC, the orange pump bracket installed at the engine plant brace would kick up the value, as those C60 pieces are harder to find.