This is going to be embarrassing, but 'civvies' don't turn me on half as much as WG's (that doesn't include out and out crack-whore street skanks), so I would opt for WG's every time. In fact, the only civvie that really interests me is my ex, and she'd rather duvet-up with a nice cup of tea and a good book.
How much would I pay for a full-on bi/lesbian FFM? About £800 to a grand, I think, which is what I'm planning on when I get my retirement lump-sum. More than that and we're into Fantasy Land, and in my Fantasy Land, they do it because I'm such an all-round Regular Guy.