Years ago, I tried canning tomatoes from my garden and it turned out OK but I never really got into it because I didn't have a reliable supply of fruit to make it worth my time.
I decided to try it again when we had a few extra cases of Tasti-Lee tomatoes left over from the Tomato Festival this year. I didn't do anything fancy with the recipe- its just crushed tomatoes (simmered all night in the crock pot) which I use often through the year- but I went out and bought new canning jars and lids (not as easy a task as one mind think- BTW, they have a decent selection in Publix, SCC). My 'canning pot' is just a standard stock pot so I was only able to fit 5 in there and I didn't buy a rack despite dire warnings of breakage. I boiled the jars with my tomatoes for the prescribed 40 minutes then my jars came out of the bath. I set them on the stove, with air space between for cooling, and waited just seconds to hear the first pop! The lid had sealed. Then... pop, pop, pop, pop! All sealed- mission accomplished! Ahhhh.... now it's time (oops past time) to go to work...:o)