I make soup mixes but I don't put them in a jar. I send then as gifts and the jars weight causes the postage to go up. Also I don't know where you live but canning jars cost around $10 for a dozen, another added expense for what should be an inexpensive gift. So I put the mix in the celophane bags the kids use at parties as goodie bags. They are really cheap somethng like 20 bags for $2. Since I like making soup mixes I got wooden spoons at the $ store they were 3 in a pack and I attach a wooden spoon to the bag with pretty ribbons.
My favorites are Cream of Potato Soup it is great for collage kids as all you do is add hot water it is kind of like cup of soup. The other one I make is a layered bean soup. At times I have made biscuit mix and have given both the soup and biscuits so that the person has a complete meal. It is a nice gift for a new mom along with a baby quilt. All they have to do is add water and let it simmer away and lunch or dinner is done. Now that I am writting this I better make sure I have Christmas celophane bags as soup will make a nice gift to include with Secret Santa and also to send to some friends.
As for jars I have baked fruit breads in the jars, when they are done baking you put the lid on and back in the oven for about 5 minutes that seals the jar. Just to see how long they would last I saved one for 6 months then opened it and it tasted as if it was just baked. The web site I got it from said they last forever. You can aslo use the 4 oz jar and bake small pies in them. You do the same thing you put the lid on when it is done and pop it back into the oven to seal the lid.