Hi Mark the shark, Paint Shop Pro is from Corel, when you visit the Corel site you can find out how much it costs.
I am from the Netherlands, soooo.. we pay in euro's so I am not sure how much it is in pounds or dollars 
But it is worth every penny.
Modelmaker, it might be worth having a look into your version 8 again, I belong to a group that makes digital drawings with Paint Shop Pro, we work from version 7 all the way up to 12, it requires practising, practising and practising though, but that doesn't suprise you I guess since you wrote you use Photoshop 