Furnace filter

[Ben C]

Hi,

Getting ready to rent out the town house I am living in now and just realized I ran out of furnace filter(Central AC). I've been using the expensive ones as kids has allergy. my question is what kind of filter do you use for rental. expensive ones that requires less replacement, or by case of cheap ones and replace often. also, is it fair to ask the tenant to replace say every month?

Thank as always.

Ben