My main concern would be that our cycle would fail, and our recipient would succeed. I know that sounds awful, but how hard would that be - knowing you have one of your own eggs growing into a baby in someone else when you don't have your own?
I did it. Mostly for the discount on the cost of my own treatment, but also because it was something I had planned on doing 'after I've had kids' and it then made more sense to do it at the same time.
The risk of 'reducing' your chances by halving your eggs is something that can be hard to get your head around. It helps that it'll be a long while before you can find out whether your recipient got their BFP. I think you have to wait until a year after your treatment. And, of course, they might not succeed the first attempt, but with a subsequent FET.
I think what made it make sense to me was knowing that anything that happened to the recipient of my eggs wouldn't actually have any impact on my treatment. I'm not really into fate or all that so found it a bit easier to remain pragmatic and focused on my own goings on. It helped that my treatment was successful, so any fears didn't come to pass.
Also worth keeping in mind - if your clinic is anything like mine, you'll be required to have a 'counselling' session which was, for me, effectively a chance to go through all the technicalities and ethical considerations of donating my eggs. (I was also using donor sperm, so had a double whammy of donor stuff to consider.)
I considered it, but instead we've chosen to go abroad. I'd love to have done it, but I couldn't shake the thought that in 18 years your half child could knock on your door. All the unknowns of the other child would eat away at me. I applaud the woman that can go through with it.
I would say though, that I don't think it's for you if it is purely for financial reasons. I think you need to want to help someone else and have absolutely no concerns about the potential other child. If counselling pick up worries and concerns you'd probably not be allowed to go ahead.
Also remember, if you don't get many eggs the donation may be cancelled and you would pay in full. Therefore you need to have the full funds ready just in case.