Ebay has oil filters for roughly 10 dollars a piece when you buy 3.

The oil is funky Euro Spec low ash synthetic if you buy it wrong it's 12 bucks a quart. Note the oil needs to meet Chrysler Ms11106

Again on ebay you can by 20 liters for 130$ Liqui-Moly meets the spec but it's not in their current literature but if you dig on ram1500diesel you can find a letter

Red