Bonded DSL Connections(Mushroom network) question?

I live in the middle of nowhere, I'm at the max internet speed. I need a solution, I found Mushroom Networks, and I think they can do what I want. I want to essentially double my download speed. How much does this usually cost(other than the doubled internet cost)...I want to be able to play games faster and upload files faster. Do I require the monthly service that is an additional cost from them? Are there cheaper solutions? Also, please don't start telling me it isn't possible to bond a connection on my side, they have gotten it where you CAN. I just need to know how, how much, and best solution for 2 DSL's. I am not currently a business, but I will eventually open a business as well. Mostly it's for gaming. I've already checked out quite a few sites about it, and there are plenty of ignorant people that keep saying it is impossible, but I know better, as does my networking teacher.