I usually buy my jars off ebay. Just taken delivery of 20 jam jars, ready for the summer fruit season. If you pick the seller, you can usually get your jar for $2 each delivered. For home use, I'm happy to recycle jam jars etc., but for gift giving I like to use new jars.
There's something really satisfying about giving jars of home made jams, sauce or spice mix, and it's so easy to pop some jam on to cook after tea.