As azsouth says, there are usually 2 different versions of blanks out there. If you put a 1.5 or a 2.5 from one supplier that you get for $1 and you put a 1.5 or 2.5 from another supplier that you paid $2-$3 for you can usually see a difference. Some guys dont care what they paint as long as its cheap in the long run it can hurt you though if you plan on selling painted baits. If it were up to me, I would rather pay more and get less lures that I know wont have issues than pay less and get more lures but the quality control isnt there.
Im not biased on one supplier or another, there are just some I would not buy certain blanks from. When you have been importing for 8 years, you see a lot of baits.