Sorry to hear of your poorly piggie. I've had two pigs who've had to have eyes removed, where antibiotics didn't do the trick. The first time was in 2005 and it cost £120. The last time, it was in 2009 and it cost £250 (granted, that included the extra £50 for seeing the out of hours vet on a Sunday.) and you don't want to know how hard the wallet was hit with one pig's investigations and treatment (useless) for cystitis at the vet hospital earlier this year, but we could have had a very, very nice holiday otherwise :(
When there is a problem with an eye, it can escalate very, very quickly. If treated very early and robustly with antibiotics, it can be fixed, but not always.
The £65 doesn't sound unreasonable at all when you think of actually what's involved in the surgery. The alternative, unfortunately, would probably be being put to sleep because the animal will be in quite alot of pain and be at risk of haemorrhage if the eye erupts.
Bonkey Mollocks idea is a good one. Things don't often go wrong with piggies, but if and when they do, it could cost quite alot. Keeping some money aside just in case can help if it does. Maybe the vet will accept payment in instalments this time?
70 is right - worth trying to get to the bottom of the problem. Often, it's just the result of a poke in a sticky out eye, but it could be underlying.
I now have a brilliant pig savvy vet (whose wife looked after the boys when we were in America and I was concerned one boar's cystitis might be coming back so was afraid to send to boarding,) who hardly wants to charge anything. Later on, it might be worth shopping around for a less costly but pig savvy vet.
Best of luck with the little porker.