I bought root stocks 106 and grafted. 10 were about £35.
As a side, I also have getting on for 200 seedlings grafting practice, field boundaries and because id like to 'discover' a new Apple. And if they just make crabs I'll graft then over in years to come. The actual seedlings I've seen aren't bigger than m25 so I hope can be encouraged to have most branches around 6'