Archer loops aren’t the cheapest but probably are the best value going right now. I usually pay about 9 bucks a loop for LP full chisel and 12-14 for full 3/8.
If you want the good stuff, member Dsell here will fix you up with Oregon EXL.
I should mention I also used a lot of Rotary brand in standard 3/8 full chisel. It stretches at first but once you cut a couple cords it doesn’t need any more adjustment and cuts on par with Oregon.