I've heard that Oxbox is a pretty good food, and Mazuri. I know oxbox can be found at most Petsmarts, not sure about Mazuri though, but I'm sure feed stores have both of them in bulk which is a lot cheaper.
As for bedding, I use fleece. I shake it outside every day and wash it every few days to a week. I've used aspen before, but that always made such a mess and was annoying to clean. Fleece is a lot cheaper!
Be careful with what you get your chin for toys! Being honest, most pet stores don't have toys that are safe for chins, even if they did they are so expensive imo. I don't have many toys for my chin right now, but I'll be ordering some online from Twilight Chinchillas, I'm super excited! Not much help there, sorry!
Be careful with what you give as treats. A single cherrio, shreaded wheat, rolled oat, or rose hip every once and a while is good. Not all at once!! My chin gets a single treat once or twice a week, I break them up into small bite sized peices so she thinks she's getting more then she is!
Those are just a few things I can think of off the top of my head.. not much help though.