Check with your local feed store. If they don't have it, they usually can order a bag for you. I think I got mine for 32 for a 50 pound bag. I read that you need real vanilla for it to make a difference. I put a bit of baking soda underneath my aspen shavings. I don't know if it really makes a difference or not. What has helped is a small air purifier with a carbon pet filter in it. I keep that right next to the tubs. All I really smell is the bedding. I dump and clean the tubs every week.
Maybe there is a rat breeder on the forum near you? I got mine from Satomi and they're sweet as can be. I got my other (biter) group from Petsmart and one from the feedstore. They've never really seemed to like me around and when they had babies one bit me, which taught the other mom to bite. My newest group though seem to actually enjoy my presence. They'll come up for me to give them pets and scratches.