There have been plenty of deals on here in the promotions/rebate section to give everyone a chance to stock up.. I think I currently have 4 6qt boxes of Havoline synblend 10w-30 ($8 per box), 2 5qt jugs of QS Synthetic 10w-30 ($14 per jug), 1 5qt Jug of Castrol 5w-30 blend ($14 per jug), 4 6qt boxes of Havoline synthetic 0w-20 ($24 per box) and 4 5qt jugs of Mobil 1 5w-30 ($25 per jug - $10 rebate). All these from Walmart, Sams or Amazon. I rarely just buy 1 oci worth of oil. Stock up when the opportunity rises. Oil doesn't go bad on the shelf.
I do agree with the current Walmart Oil/Filter situation the best deal can be a bundle at the parts store these days if you just need a one off, but if you have a garage and space then get yourself a little stash and rest easy.