Do people buy fixed cats?

[SFE]

People would def buy a fixed cat! Most people fix their animals, and if they don't it's only because they are uneducated/ignorant.

This is the best thing for the cats, I think you should do it! (IF you can afford it of course)

Some people don't want to deal with the kitten stage and are actually interested ONLY in older cats.

Usually (if you look online especially):
People will only sell cats that are fixed.
If a kitten/cat is not fixed, and isn't up to date on shots/medicine, they usually are FREE.
Shelters in my area tend to sell fixed/up to date cats for $100-150, but usually when individuals sell cats (fixed/up to date) it's a bit less than that ($50-80).

You can try to use sites like Kijiji to find new home owners for the cats.
You can try to find local groups on social sites (facebook etc) for animal adoptions.
You can call/talk to the SPCA or a local vet clinic to find out what options they can advise you of!