I think your best bet is to watch the sales at Sprouts. At least twice a year (sometimes more) they have roma tomatoes on sale, 2 lbs /$1. When they do this, I buy 50 lbs and take them home and can them. Growing tomatoes in this climate is tricky; growing enough to make it worthwhile to can is nigh impossible. I tend to wash the romas and toss them into my gigantic turkey roaster with onions and peppers, roast the whole batch for a few hours and blend them into roasted tomato sauce which I then can. My advice? Try growing heirloom slicing tomatoes instead. Good luck!