Most value, with best oil and oil filter:
Walmart or walmart.com, buy Mobil 1 Extended Performance or Castrol Edge in the gold jug, 5w-30, either in 5-quart sized jugs.
Then, put on an extended life oil filter, the Fram Ultra in your size, an "XG2" no matter which engine you have. Then change your oil once a year, adding oil as necessary of course.
Plan B: Buy any name-brand synthetic oil such as Valvoline, Castrol Edge, Mobil1, Pennzoil Platinum, SuperTech you want and change it every 6 months. Always a good idea to use that Fram XG2 oil filter though, since it filters better with lots of dirt capacity.