Rice Use Basmati rice as far as possible.
Coriander seeds Buy the seeds and powder.
Cumin seeds Buy both kinds - white and black. Get seeds and powder of each kind.
Dry red chillies Get them whole and you can grind them coarsely later if the recipe calls for that.
Fresh green chillies Buy just a few at a time.
Turmeric Buy only in the powder form.
Garam masala Buy garam masala readymade in the stores or make your own.
Cinnamon Get this in stick form.
Cardamom Available in three types black, green and white. Buy just a little of each type.
Cloves Like cinnamon, this spice is also typically used whole in Indian cooking so buy it that way.
Peppercorns Most often used whole. If required in a recipe in its powdered form, grind it fresh just before using.
Bay leaves Use it to neutralize strong odors in cooking.
Poppy seeds Buy these whole.
Mustard seeds Buy these whole.
Fenugreek seeds Typically used whole.
Aniseed/Fennel seeds Buy whole.
Asafetida Store this strong-smelling spice in a tightly closed container as it can easily impart its smell to other spices.
Thymol Buy seeds.
Saffron Buy just a little.
Tamarind Sold as blocks. Buy a small block.
Raw mango powder Store in a cool dry place or else it will get lumpy.
Ginger Buy in both paste and whole form. You can also make your own paste if you are so inclined.
Garlic Get both the paste and whole pods.
Oil I like to keep vegetable/ sunflower or canola oil in my kitchen. Mustard oil is required for some East Indian dishes. Keep a small tin of ghee on hand for when you want to make something special.
If this seems like a lot to buy just to get started, consider the fact that you will use most of these ingredients fairly often. Also while a dish may have many ingredients and therefore seem to be time-consuming and difficult to make, it might actually be easily assembled and prepared. Always read the recipe from start to finish just to make sure. The result will, needless to say, be worth all the effort!