Not every Walmart carries canning supplies. Those that do will usually carry them as a "seasonal" item - and that can be a strange season sometimes ... I know the store where my son works doesn't get canning stuff in until somewhere between October-Jan and has it cleared off the shelves before June!
You can
order one online and they will ship it to your local store for free. They have both the Ball water canner starter kit and a pressure canner.
You will see several of us keep referring folks to the
National Center for Home Food Preservation for a reason ... they have the current accepted methods and a lot of information for free. I have the also often referrred to
Ball Blue Book - but I use both resources. Go to the NCHFP site, and then under
How Do I? (on the left hand side of the page) click on
Can for general information on canning, then you can click on
Canning Tomatoes and Tomato Products and then click on what you want to can. They will tell you how many pounds of tomatoes it will take to make what quantity of that product (along with instructions for the procedure and sometimes a recips), such as this for
Standard Tomato Sauce:
"
Quantity: For thin sauce – An average of 35 pounds is needed per canner load of 7 quarts; an average of 21 pounds is needed per canner load of 9 pints. A bushel weighs 53 pounds and yields 10 to 12 quarts of sauce-an average of 5 pounds per quart.
For thick sauce – An average of 46 pounds is needed per canner load of 7 quarts; an average of 28 pounds is needed per canner load of 9 pints. A bushel weighs 53 pounds and yields 7 to 9 quarts of sauce-an average of 6½ pounds per quart."
Canning supplies like jars, lids, pectin and pickling spices I got at the Albertson's grocery store down the street from where I lived if Walmart didn't have them in stock. They were as cheap as anywhere else in town - by the time you figured in gas and driving time. If they didn't have what I wanted I could go about another 1/2 miles to the Tom Thumb - they carried canning supplies year round, too.
I have to admit - if you are not growing them yourself it's cheaper to buy them already canned.
Hope this helps you some ....