It has happened to all of us, you are trying to make a dish from your home country and the ingredients are not sold in the local market. Or they are, but are prohibitively expensive. You can either moan about it, or get creative. I chose to get creative. This page will include a list of substitutions, as well as some recipes for products not available.
Bacon: Turkey pastrami works as Turkey baconish. I also use it as a base for soups sometimes instead of salt pork.
Brown Sugar: 2/3 white sugar and 1/3 pekmez (dut or grape works nicely, carob does have a stronger taste if that is what you prefer.)
Buttermilk: Kefir (If you are able to get it I love AOC brand the most)
Chili Powder: 1 tbs red pepper, 1 tbs sweet pepper (paprkia), 1 tbs cumin, 1 tbs garlic powder.
Cream Cheese: Labne
Salsa: Acili Ezme with chopped cilantro (Kişniş) stirred in.
Sour Cream: Süzme yogurt with a little krema stirred in. It works best if you let it sit for a few hours before serving.