Let's break the question down, shall we?
Toffee: Sweets made from sugar, molasses (sugary syrup) and butter
Tuff: Rocks made from volcanic ash
Toff: A rich person of high class
So overall, if the toffee (candy) was tough (strong) as Toph (that's you, so it's like literally rock candy) and You are only tough as tuff (as in a volcanic rock) and the toff (the rich upperclass person) was selling the candy at a high fee, how much are you willing to buy?