Kitty I dont mean to be patronizing at all, so apologize if it comes over to you like that.
Purrs peeps between them have so many cats and so much experience and we have seen some of the problems caused by bad breeders and others who are determined to push sick kitties onto others who are desperate for a cat.
We also know that unless you go and see the kittens and find out exactly what the situation is where they are coming from, you may even then be hard pushed to find out the truth.
To be very very blunt, it sounds like you are not very rich if you need neutering vouchers and you dont drive. You will not get insurance on that eye as someone else has said and how will you be able to afford the treatment?
You have to be very realistic here and I know you are desperate for a cat but it has to be one in a locality close to you where you can go and see it before taking it on, or where CP will transport you to look at their cats as my Cp did for me, cos at the time I couldnt drive either.
It sounds like you need a cat who is already neutered and has been vacinated, fleed etc and yes there will be a donation needed and a home check. If you are trying to avoid these then this is not good for your future care of the cat.
All kittens and cats without homes need one but its very important that they go to the right home, all kittens and cats do not fit with every slave. These kittens already have a home with their breeder and if she is saying anything else, you know what sort of breeder she is!!!!!!!!!!!!!
So however cute they are you need to have enough finances to be able to insure them, feed them and look after them as they need.
I agree with who ever said that you are leaving yourself open for trouble and that there are warning bells here.
You need to be so very very careful and you should not rush into this.