The most i spent was was £550 (Google says that's $770) on a super banana, That's only because I cant be dealing with the hassle of a male only maker.
Other than that My limit would be half of that for something special.
There are a good few I want that cost more, but I would rather wait until the price comes down, as is always the case eventually with newer morph combos.

That's of course unless I win the lottery.