I'd add that Freestyle is in the process of switching from Ilford and Forte (Arista Pro and Arista.EDU) to Agfa and Foma (Arista II and Arista.EDU Ultra) as their film suppliers. The Ilford and Forte stock is, AFAIK, in comparatively limited supply, and some of it might be short-dated by now. If you like the stuff and the price is right for the Ilford and Forte material, buy up as much of it as you think the price justifies. (Personally, I've got three unopened 100-foot 35mm reels of Arista Pro 50 in my freezer.)
The only ISO 100 Arista product I see that costs $1.29 per roll in 120 size is Arista.EDU Ultra when bought in quantities of 20 rolls or more. That'd make it the rebadged Fomapan 100, which should be available for the indefinite future. I've only shot one roll of this emulsion, and that in 35mm, so I don't have strong opinions on it one way or the other. I do very much like the Fomapan 400/Arista.EDU Ultra 400, though. There's something about the grain structure that appeals to me, but that's just a very subjective and ill-defined sort of "I like it" reaction; I can't be very precise about it, I'm afraid. Your best bet is probably just to buy a few rolls and try it for yourself.