Mobil 1 Synthetic 10-30w from Walmart
Here in GA you can buy 5 qts for just over twenty bucks, I checked most places online and they had the best prices..
I have been reading some oil forums and while I never believed in synthetics on my 20 year old 10 hp Tecumseh, that I changed the oil once a year,, I used any quality 30w oil and it's still running fine.. With my new Intek my plan is to change in twice a year with synthetic.. I read most wear happens at startup and 10-30w helps lube better at starts..