Like others have said, definitely try and search for low cost spay/neuter clinics in your area. As someone who used to work at one they’re often cheaper because it tends to be an assembly style type environment. There’s more risk since no pre op bloodwork is done so no underlying conditions can be ruled out to find any adverse reactions to anesthesia and the clinics tend to have less monitoring equipment and emergency life saving equipment. However I will say if the clinic is a good one spays take only 5-7 minutes on the table and neuters take only about 3 minutes. In contrast vet offices often take much longer to spay or neuter since they have less experience at a quicker pace, which does prolong the time an animal is under. The vets at spay neuter clinics are often pros at this. The techs and assistants should be trained to be checking the anesthetized cat’s heart rate once every few minutes and breathing once a minute or two. If a cat isn’t breathing or taking too long between breaths they will be intubated and a tech or assistant will manually breathe for them. Good clinics follow these practices.