how much does the anal sac gland surgery cost?
I don’t know, but it shouldn’t be outrageous, its effectively surgicalremoval of two sacs/glands near the anus. I’d guess probably a little pricier than a neutering since its not as common, but not horribly so. But you’d have to call a few vets in your area and ask.
Check with your local vet (possibly the same one who did the neutering surgery?) and they’ll give you a price. IIRC, it’s not outrageous.
I’ll do it for $20. If you can provide a sharp knife or cheese grater.