I wouldn’t buy the generic jars Wal-Mart sells. I bought a couple boxes a couple of years ago, and nearly every one of them had hairline cracks in them. Made in China, of course. Ball brand canning jars are still made in USA. They last literally, forever. I don’t know about Mason jars. When I was a kid, my mom saved mayonnaise jars and used them. We never got poisoned, so I guess they were safe. She didn’t have a pressure canner, either. She canned tomatoes, corn and green beans using the boiling water bath method. I know you can open kettle can tomatoes without processing, AS LONG AS THEY’RE NOT LOW ACID tomatoes. But that’s tricky, with all the “new and improved” tomato varieties.
My mom also used used mayo jars for canning and they were NEVER a problem. She used those because we couldn’t afford to buy canning jars. The only jars that ever cracked on her were the Ball jars. The mayo jars NEVER did.
I guess the Ball people didn’t like that much because after a while the the mayo people changed the mouth size a hair and the lids didn’t fit right any more.
We figured that it was because it cut into the selling canning jars market too much.