I would like to know more about turbo tax's guarantee that they can get me the best refund. I'm almost done completing my form and don't want to pay $90 without more info

The site wants to charge me $90 to complete my 1099-b. currently i've completed everything on a different site and am getting a greater refund for both state and fed. I'd like to finish on turbo tax to see which one gets me a greater refund. I'd like some more info on how this works.