Cardamom is a spice that is hard to pin down. Like cloves or cinnamon, it pairs well with sweet or savory. It is perhaps best recognized as being that flavor you can’t quite place in things like Thai iced tea or Indian curries. It is also a spice that is ready to take its place alongside ginger as a versatile flavor for everyone’s kitchen. Any Indian or Middle Eastern grocery store will have both varieties for a good price; Patel Groceries on Central Ave. is a good place to start.
Consider starting your journey in cardamom with extract. Use green cardamom (not black, which is more nut-like and has a slightly more astringent flavor and is sometimes smoked.) Fill a small jar with cardamom pods, partially crushed. Cover with vodka and let sit for up to 2 days. It quickly becomes bitter if left to sit longer (unlike most extracts which require weeks of soaking) so strain out the solids and keep the liquid with your other extracts.
Consider cardamom extract anywhere you would use vanilla, especially to make a sugar cookie more sophisticated.