I am shopping around for alternatives to the very expensive Polaris motor oil. The manufacturer recommends the Polaris brand 5W-50 for my Sportsman 570, but I'm wondering if something less expensive would be suitable. There's got to be an alternative out there. I mean, there are so many brands of ATVs, cars, trucks and everything else that must take 5W-50. There's got to be something that doesn't cost $43.99 for a gallon of oil. Any ideas?