Where can I get a feral cat spayed for free?

You can try Faithful Forgotten Friends they're out of Holy Family Church behind the church on 1st and 3rd Tuesdays. Also SOS is very reasonable for spaying/neutering.

Nothing is free. Call cat welfare for a voucher then take the cat to SOS

You get a voucher from cat welfare and take S.O.S will honor it.

Yes

How old does your kitten have to be to get neutured