as lilratsy has said, the prices and safety will greatly depend on the vet you use. i have 2 vets that i use. only one would i trust to do a neuter and neither would i trust for a spay. they are both competient vets and i trust them with my rats lives on more then one occasion, but one vet has not ever done a spay or neuter on a rat and given what i've seen of cat spays and what the vet tells me, they just don't have the fine enough equipment for a rat spay on such a small body. i would definitely want a vet that appreciates the size and difficulty because of it and has the proper equipment and knowledge with rat operations. it is dangerous to use a injectable anesthesia, as it is easy to overdose and difficult for the rat to metabolize, so they need to go under the gas alone whenever possible. i trust one of my vets for neuters as she has done MANY rat neuters in the past and with wonderful results. the boys are feeling back to themselves by the evening, never have i experienced scaring from her neuters and only once was their post neuter abscesses (but that was on a rat that we later found out was VERY easy to abscess). whereas, other vets that have done neuters have left scaring. this doesn't seem to bother the rat itself much though it worried me. magi was done by a vet in halifax, he had scaring and had to be on pain meds for a few days after the operation, whereas the only i have done here had a pain reliever after surgery and did not need another dose after the first had worn off.
that is my experience with neuters and my thoughts on spaying though. spaying has HUGE benefits in dropping tumor incidence rates to from over 80% to under 10%, a drop in likihood of tumors by over 70%. that's quite significant. however the males have some health benefits as well, hormonal aggression is eliminated and in both genders it is reported that the altered animal will live longer on average.
do remember though, that after a neuter, the male is still fertile for 3 weeks so no interaction between males and females until then. if the female is spayed, they can be together as soon as the female is back on her feet after the operation, assuming that the male and female know each other; otherwise, introductions can begin instead.
if i had the money for it and a vet that i trusted to do the operation i would have my females spayed as well. as it stands for me now though, i do not have that kind of money nor the vet. instead i have my males neutered. this is because i am horribly allergic to intact males, as well as i have females and want them all to live together and have a vet in my area that i can trust with their neuters.
when finding a vet to do this surgery ask them how they anesthetize(you want gas, not injection), do they take out the fatty tissue as well (in reference to neuters (my vet does this as she claims it lessens swelling and scaring, thus less pain and chance of infection)), how long does it take for the operation, what is their history with this operation on rats, at what age do they do this operation (they may give you a different age depending on the gender), then finally the price. other people may suggest that you have them on antibiotics before and after the operation and insist on pain meds. you should ask if they are given pain meds after the operation as well. of course, when calling around the first question would be to ask if any of the vets in the clinic does spays or neuters on rats. you will likely find that this will be the only question you will need to ask in many places if your area is anything like mine. many vets do not even see rats. however, it is very important that you find a good rat vet as you WILL need them even if you opt not to have a speuter done. rats are wonderful creatures and normally quite hardy in what they can bounce back from, however their lungs are very delicate and they are prone to cancers and benign tumors. at some point during your rat's life s/he'll need to see a vet and it is always better to have one lined up instead of having to find one in the time of need.
ok, my ranting is over. i hope that i've helped somewhere along the lines there.
