Ace Hardware, although somewhat expensive, will sell just about every replacement part needed in a Villages home. The nearest to the new Lowes is in Wildwood Shopping. It's on 301 east side between 466A and 44, it's the center that has a post office on the end.
I've been buying my filters from Amazon for the last few years. Here's what I buy, a 3 pack with free shipping for $50. Looks like they've gone up to $57.
US Home Filter SC80-16X20X4 MERV 13 Pleated Air Filter (Pack of 3), 16" x 20" x 4" - Replacement Furnace Filters - Amazon.com