The best of breeders will absolutely negotiate costs with you on such a kitten. The ones who are only interested in lining their pockets will not be so enthusiastic about dropping the price.
SolarityBengals posted the link to Mama's thread, which has a wealth of information about heart murmurs and anesthesia. If you haven't already taken the time to read through that (it is a bit lengthy - but chock-full of really helpful information) then do that first.
Here is the link just so you don't have to scroll *grin*http://www.thecatsite.com/forums/showthread.php?t=75732
Then, make an appointment to speak candidly with your vet about options for anesthesia after he has had to chance to meet and examine this kitten. Taking into consideration many factors along with the findings of his exam, he will formulate a treatment plan which will ensure the continued good health and longevity of your new baby. Make sure to ask educated questions - do your homework before you go. Write your questions down and do not at all feel embarrassed to take notes. You are the first line of defense when it comes to the health of your pet. Your vet is there to assist you, but the final decisions are yours. You do have choices. You do NOT need to blindly accept that whatever your vet suggests is the right choice for YOUR cat. Research, read, post here ... do whatever you can to learn, but know what you are fighting.
One of our esteemed Vet Tech members is Dr. Doolittle and as she tells me, anesthesia is her favorite topic. We are also blessed to to have other, very knowledgable Vet Techs as members here and I am sure that any of them would be happy to help you decipher what your vets discusses with you should you find you have questions about it.