Is the $10.00 cartridge filter at the pool store any better quality than the cheaper ones at Lowes or Wally World? The Wally World one carries the same brand name as the pool, so is it the same as the filter that came with the pool?
IF you are talking about the intex filters then there is often a difference. The intex branded ones are paper and are meant to be thrown away and not cleaned. Many of the more expensive replacements sold at pool stores are polyester (just like the cartridges used in larger pool filters) and are cleanable so they are actually a better value for the money.
get two of them and that way you can clean one and soak it if needed while you still have a filter in the pool. Every 2-3 months (assuming weekly cleaning) soak the cart in a solution of 1 cup of Cascade or Electrosol or other automatic dishwahser powder to evey 5 gallons of water. Soak overnight and hose it off well the next day. Your pair of carts should last for years if you do this.