SQ has summed it up well.
Vet costs vary widely, it's all contingent on what the vets who are available to you charge. $85 spay is incredible! Here, even with a Rescue discount, my local Rescue pays $300.
If you're checking prices for spay/neuter/tumor removal, remember to add the cost of the initial exam. And if a girl gets a tumor and you have it removed, you should spay at same time or she's likely to soon get another..
And I echo that it's important to not just have a vet, but a Rat-Experienced vet. I learned that painfully..
I understand the vet cost concern, as I'm on handicapped assistance so money is tight, and that's always been my Con to having them too. I keep a Vet Fund envelope I add anything I can to, and Never touch except for them. I crittersit cage-type animals, jobs aren't frequent but it all that goes to their Vet Fund, you may be able to do something strictly for their Vet Fund envelope so it builds up over time?
Over 20 yrs I frequently wrestled with the agony of being financially unable to remove tumors, and felt it was unfair to keep having them. But I gradually came to decision that ratties might have a 1-2% chance of getting a home that will provide any surgery, most will end up in homes that keep them in a small cage with minimal outings, poor food & and no vet care at all. Mine are always treated for problems that don't require exploratory tests or surgery, I live alone, don't work, nor do I socialize much, so they get plenty of time, space & enrichment. I researched to give them the best diet, and I'm available 24/7 when they are incapacitated or at end-of-life. I figure very few lives are shortened due to lack of surgery they'd have had if I didn't adopt them, while every single one is happy & gets the best in every other way (that's not bragging, that's weighing my right to put their lives in my hands). I'm trying to say that just because you can't provide Everything doesn't mean you can't give a kid a fantastic life they wouldn't have had if you passed them up and they went elsewhere.
By the care & concern I hear from you I think they'd be lucky to have you.
- and if you find they're the perfect pet for you, then once you're Well-Experienced with respiratory problems (the most common issue) you'll know when they need meds and can buy them online for cheaper, avoiding a vet exam cost, which will help you to keep having them.