In that case - might I suggest you get married in the US and then apply for the Spouse visa? You'll still have to pay the fee for each person, but if you come over on Fiancee Visas and THEN get married, you'll have to pay the fee for each of you for the visas, and then again when you apply for the FLR (Further Leave to Remain) after you get married. So you're looking at a lot of money.
I mean, I don't know what your plans were - you have to balance the cost yourself. But as it's currently about £250 in person (a little cheaper by post) per application for the FLR/ILR - that is a lot to balance against. :-/