Canning jars run about $6 to $7 for a dozen. Considering that you use them over and over again this isn't too bad. However, it does increase your start up costs quite a bit. And if you're like me, you're always giving away your creations with only about half of your jars coming back.
There are cheaper ways to stock your shelves with canning jars. And, no, I don't mean to use mayonnaise jars. Never, ever re-use jars from commercial products from the grocery store. Only real mason jars are safe. Commercial jars are made to only be used once. Re-using them could spell disaster. They can explode in the canner, not only ruining your food, but possibly causing you personal injury.
To find inexpensive, yet proper, jars ask acquaintances and look to thrift stores and yard sales.
Last year, I found mason jars at 12 for $0.99 at the St. Vincent dePaul store. This year I paid a little more: $1.20 for 12 at Salvation Army. Pretty great deals! Give your local thrift store a call to see if they have canning jars in stock.
Most of my jars have come from friends and family. They find out that I'm into canning and they offer their unused jars. Mostly elderly folks who no longer can and love seeing the tradition carried down to a new generation.
I occasionally come across jars at garage sales, but they're a little harder to find that way. Plus, you need to be careful. I've had some people try to pass off mayonnaise jars as wide-mouth canning jars. You can tell the difference by looking closely at the jars. Canning jars will say Mason, Kerr, or Ball on the side. They're also heavier than commercial jars.