Hi Pagey... just thought I'd share my experience with you. I'm from the other side of the fence (a recipient) but my donor is an anonymous egg-sharer.
I can't see where you're from - I'm in the UK, so if you're not, none of this may be relevant.
At the CARE clinic it works like this:
Women who are accepted as egg sharers pay only for their drugs - all of the other fees are picked up by the recipient ... CARE will give you a prescription to source your own drugs if you want them too - and for donors this can be well worth it. Check out ASDA pharmacy, they had pledged to sell the drugs at cost price (i.e. around £1,200) My drugs on the other hand were only £150 so not worth the faff to get them myself.
To be accepted as a sharer you have to be under 36 and not have any of a longish list of physical and mental health problems.
As sharer, you have the right to change your mind right up to implantation (though I seriously hope no donor would change her mind in between fertilisation and embryo transfer)
When the eggs are harvested, they are divided into 2 piles - no attempt is made to grade them...they just get split equally.
If there is an odd number, the recipient gets the extra one
If you produce less eggs than a certain number (and I can't remember what this is, but it's around 10-12) you have a choice:
You can either keep the eggs - but if it doesn't work you would have to pay full price for any future goes
or, give the eggs to the recipient ... in which case you get another go for free where you get to keep all of the eggs
you are able to find out if the recipient was successful, but she will never know if you were. Any child produced would, at the age of 18, be able to track you down (but via a third party - not just a knock at the door)
here is their website https://www.carefertility.com/donation-programme-sc3/donating-eggs-and-embryos-sj3/
If you're not in the UK this won't be much use to you - but if you are it's defo worth a look