If they're like me, it's not about the cost. It's about the design.
First, they're gross. They look nasty, imbalanced, and cheap.
Second, they're confusing. Many of the dice look close to existing dice. (The d16 and d24 look almost like a d20.)
Third, they're basically unnecessary. Mathematically, what's the point of a d5 when you have a d4? A d7 when you have a d8? Is the mathematic probability changes important enough for the added complexity?
Fourth, some of them just roll badly. The edges are too smooth or too small. Some of them roll clear across the gaming table, don't stop on a good edge.