Napa is having a "Farm Filter Sale" on Napa Gold (Wix) filters until Oct 10. I picked up some 1515 (2 masterpacks, 12 count each 1515mp) for 2.87 per filter. Ford 7.3 power stroke filters (1734)for 9.17 per filter. This is about half price. If you just need one or two of the 1515 or 1734 I think the price is good for single filters, not just the master packs.