Amazon has two Purolator Classic air filters that fit late model Ford Mustangs for under $2 each.

Purolator has a $5 rebate for purchase of two air or cabin air filters, any combination.

Be forewarned Purolator's chosen rebate handler, Inmar Rebates, has a very poor reputation. My personal experience is they automatically deny every first pass on every rebate submitted. Once this happens though I've contacted Inmar using either the contact form on their web site or by phone detailing why their initial determination is bogus, my rebates have been approved. An extra step and hassle that shouldn't be necessary but it is what it is.

Edited by Nyogtha (06/26/17 08:31 PM)
“He who does not value the teacher, Or greatly care for the material, Is greatly deluded although he may be learned." - Lao-Tzu