Although some decent spice blends are available from my local grocery stores, I've found a whole new world of tastier and more interesting blends online. Yes, I could make my own spice blends, but I wouldn't get the variety I can get by ordering online. And, yes, I know I have to pay shipping costs for anything I order online, but my husband's health & contentedness with his low sodium diet is worth an awful lot to me. Penzey's Spices is a wonderful source I learned about from Cooking Forum members. You can buy most spice blends in several sizes and either in plastic bags or glass jars. The quality is so good and the variety is almost mind boggling. My favorites are the Adobo, the Singapore, the Jerk, and the Mural of Flavor seasonings. I have purchased several different ground chili peppers, curry blends, and single herbs or spices from Penzey's too.
The Spice House is another good source. I use their Salt Free Spicy West Indies Barbecue Seasoning in my barbecued beans recipe. Savory Spice Shop has several unique blends. I especially like their Black Canyon Chili Powder. It contains cocoa & cinnamon, so it taste like mole. The Za'atar blend makes a wonderful bread dip when mixed with extra virgin olive oil and some crushed garlic. I have yet to order from American Spice, but many of their blends are intriguing.
I feel confident ordering from the sources cited above because they all list the ingredients on their spice blends. So it's easy to find the truly salt free blends. Once, when I was sick, my husband did the grocery shopping. I was out of chili powder and needed some for that evening's dinner. He picked up some McCormick's chili powder and, later when he got home, we discovered it contained salt. We were both surprised because we always thought chili powders were unsalted. Another reason to read labels carefully!