Tanya, I have looked into buying aftermarket filters and they are about the same price as the NH dealer charges. Have you asked the dealer for them? As far as oil, DELO 15W40 is as good as you will do. The sell that at AutoZone, etc., but I recently saw it at Walmart for about $4/gallon less for the exact same oil. We have used that in all our tractors (at the dealers suggestion) for many years and are well satisfied. It's about $13/gal at Walmart and about $16 or $17 at the dealership and the Autozones of the world. One easy way is to write down the numbers on your filters that are currently on your tractor and just take them with you. If there is no NH dealership near you, then Napa has an online cross reference chart that is very good and easy to use. BTW, you need to change other filters more than likely....such as hydraulic, etc. Also, some tractors have more than one fuel and hydraulic filter. Do you have the operators manual? If not go on ebay and buy one immediately. Good luck and have fun!!