^ Agreed. I have both artificial and real in all my enclosures. Michaels is great for the artificial stuff. You can usually get a weekly 40-50% off one item per order too. Good luck! Let us know what you find.
The dollar tree would be a great place though. Walmart's stuff can get a little pricy if you are purchasing a lot. The dollar tree would be good since it's all a dollar!!
Of course that's mostly just foilage and flowers. You can get bendy branches and stuff from the pet stores though!