I love to can and freeze, and like you, give for Christmas gifts. My grandma taught me about turning upside down to seal but I've never seen anyone else do it.
Like beekeeping, I've never found canning/pickling anything to be especially cheap, but you just can't beat the taste and satisfaction of home canning/gardening. Just set out my lettuce, cabbage, and beets in the garden last week, and started my tomatoes and pepper seeds. Yesterday I tilled/limed new ground to expand my garden, and my package bees will ship to me this week. I'm pretty happy