I mix most of mine along with making salad dressings. Yes many people share their favorites here and many other sites and if I think it might fit my taste buds I give it a try. Many websites can be found to "copy cat" close to common brand items to make my own.
Like you I am not a big salt person but more importantly anything with MSG really messes me up for 12-24 hours and is included in a lot of commercial rubs and dressings.
I usually find a recipe that is close to what I have been putting together for my taste buds, like "Jeff's Rubs" for example but sometimes I try a little twist on the next batch to see how it works for me to fine tune it for my taste buds.
Yep, I have a cabinet full of spices that have saved me a lot of $ long term from not buying a Commercial brand, but just mixing a small batch of a close recipe and finding out I may not have not cared for it.
I see you are in North Texas, I have found Atwoods Farm and Ranch Supplys around here usually has a surprising large selection of seasonings at very reasonable prices if you happen to have one in your area to start with, Amazon
is my choice if you need larger quantities.
Good luck to you finding what fits best for you.