First of all, please forgive the camera flash that makes the end result at right look less red...it's actually only slightly less deeply colored than the original salsa. I must learn to take better pictures!
Starting with the cheapest salsa I can find, I add a 14.5 ounce can of diced tomatoes and then some pepper jelly to taste. (One batch of pepper jelly freezer jam I made never set up so it finds its way into salsas and soups...gotta use it up somehow!) If I didn't have any pepper jelly on hand, I'd probably stir or smush-in whatever flavor jam happened to be opened in the fridge, as I'm a fan of slightly sweet heat. I usually buy medium heat salsa & end up with something just barely hotter than mild, but if hot salsa happens to be all I can find on sale, that works for me too.
If avocados are in season, I'll cut one up and add it to a little of the salsa, making sure to end up with only what can be eaten in one or two days before the avocado turns. And of course, when our garden's in full force, we make fresh salsas, but in wintertime, this'll do.
Next harvest, I'm hoping to spend some time dicing tomatoes for the freezer, so I won't have to buy the canned tomatoes all winter, but with a generic 14.5 oz. can of diced tomatoes going for around 63 cents, unadorned canned tomatoes are still cheaper per ounce than salsa. Incidentally, for anyone concerned with their salt intake, adding no-salt tomatoes helps lower a salsa's salt content.
Okay, that's one of my little easy-peasy ways to stretch our grocery dollars. Anything being stretched in your kitchen these days?