We spend mucho dollars on quality primers, paints and clears. Fillers on the otherhand cost from $10 to $30 per gallon on average and are fairly inexpensive. A quality filler like Rage extreme can reduce abrasives usage by 50% and the time spent sanding. Every time I buy some elcheapo filler to save a couple of bucks on the initial purchase I end up losing money with abrasive waste and wasted time. Do yourself a favor and don't buy the cheap stuff.

I wonder about that too.Polyester must be real cheap to make. Polyester primer has a lot more solids than Urethane primer and is much thicker yet a gallon of poly primer is half the price of urethane primer.