The indian recipes I'll post use lots of spices, many of which you probably already have (cumin, chilli powder, black pepper corns, cinamon sticks, cloves...). The rest can be found at any Indian grocery, and probably most international food stores and Asian food stores. Sometimes it's a good idea to buy your spices from stores like these, because lots of times they're cheaper. But a lot of them come in large quantities. So you can share with somebody, or just store some in small containers to use when you cook, and the rest in an air tight container out of the way. Sometimes it's enough of a bargain that you could toss all the excess and still have saved money.
I mention this becuase Jennifer asked about asoefatida. ( This article on the stinky spice falls into the "tmi" category; I find the fifth paragraph very entertaining.) I think you could just leave it out of everything, and it would be ok. Maybe it's just supposed to bitter things up a tiny bit, just for balance. I bet it's the same concept as adding salt to deserts, only not as necessary.