i got my first chin from a pet shop (pets at home). i went to get some hay for my guinea pigs, saw him and would not leave without him. he was the biggest, healthiest chinchilla and then we got fluffy - i live on the isle of man and there's a small pet shop whose owners breed chinchillas (but only have one breeding pair so not many litters) and they go to england and get animals from breeders and bring them to the island. so that's how i got fluffy. unfortunately, fluffy was sexed by both these breeders as a boy while she's in fact a girl - we only found out when she gave birth to three little babies. chinchi had to be snipped and sadly developed an infection and died after he had a reaction to the anaesthetic after a corrective surgery
fluffy has teeth problems but the vet isn't sure why. her back teeth grow at an angle but the vet thinks the overgrowth looked like several months affaire, up to a year.. but she's nearly three... so we're not sure what's going on. she's had four babies and they obviously stayed with us - they seem ok so far so fingers crossed.
my latest addition is mae. i rescued her at the end of october last year and she had about a week to live, the vet wouldn't even attempt to get an xray of her teeth because she was so malnourished she wouldn't have made it through the anaesthesia. i thought that if i could give her a few weeks in a nice home, it would be worth it. nearly a year on, she's thriving and now lives with one of fluffy's sons (he's neutered). to start with, she had teeth problems, gut problems, respiratory problems, chronic jaw bone infection and she only has three legs. her teeth have only been done once (she had one pulled out as well!), she still has gut problems so i have to be very careful with what i give her to eat, she still has respiratory problems but we can manage them so it doesn't even bother her anymore and the jaw bone infection we can do nothing about but she doesn't seem to mind it at all. she is the most affectionate, sweet little girl but obviously does require a lot of time. i wouldn't recommend getting a sickly rescue (healthy rescue by all means! it was absolutely obvious that mae was really unwell from the start) as your first chinchilla though. as rewarding as it is, it's hard - for the first four - five months i didn't know if she was going to make it - and they're incredibly good at hiding they're not feeling so good. i pick up that she's not well a lot sooner now than i did when i first got her although we do have a visit every now and then when she seems a bit off to me and the vet can't find anything wrong with her. but that's the better outcome than the other way round!
i think i would go the rescue way if i was getting another chinchilla, if i could (little island, not many rescues although i have seen somebody rehoming a couple of boys since i got mae). sure, you have a better chance of getting a chinchilla with less genetic problems from a reputable breeder but that's not to say that the chin won't develop a disease that's not linked to her lineage. they're awfully badly designed animals.
whatever you decide to do, good luck! hope you'll find the right boy/girl!