Well thats a broad question, it would depend on what you're looking for. I personally shop at the places that offer the best customer service.
If it's parts you're looking for, we have tons of stuff at www.eastendmachining.com, and we take pride in working harder than humanly possible to take care of our customers at EEM. I was a long time customer of EEM before becoming an employee because I come from a long line of business men and women and I know how rare it is to find someone who runs their business the way Joe does.
completely forgot about putting up this post... thanks Charlie for the advice- i question was pretty vague so ill elaborate. what sites are do you guys use for stock replacement parts, and stuff like tires and bodies?
Several stores on ebay have been good to me too. Before discovering eastendmachining.com, and then later becoming an employee, I ordered about 95 percent of my stuff through ebay, and never been screwed yet by buying from reputable vendors.
We have a huge selection of stock replacement parts in stock at East End Machining, I'm always amazed at the inventory, and I work there lol.
The only site I would add to that list would be www.davesmotors.com but that's for large scale stuff like the FG Monster Truck, HPI Baja, etc. Between the five of them I too am like Rolex... broke.