The cannery is located in Jacksonville and it sounds like it could be a decent way to cooperatively can foods in a cost-efficient way. So, say, you have a group of homesteaders who grow tomatoes and end up at harvest with a ton of tomatoes and then someone goes, "you know who has the best recipe for pasta sauce? My mimi," and everyone goes "yum, homemade pasta sauce!" So you get your bushels and bushels of tomatoes, load the kids and the moms in a couple of minivans (here, I'm assuming the only folks with enough stamina for this kind of activity would be moms and my apologies to non-moms) and drive up to Jacksonville and use the Duval Extension Canning Center.
The IFAS Solutions for Your Life page for this facility says that it costs 7.50US/hour to use their equipment and you bring your own jars if you are using glass (I guess they provide aluminum cans if you go that route?). There is an additional 0.15US/pint jar and 0.30US/quart jar processing fee which I'm assuming is for sterilization and perhaps a lid (the author seems to be a little reticent about certain details like this, I guess assuming you'll agree that 15-cents or 30-cents is an awesome deal). I don't mean to rag on SFYL; the site is awesome since it makes all their fact sheets and extension guides available to anyone with an internet connection, and there is a lot of information on topics like this.
As a final note, if you are not in Florida, or in the northern part of the state, Pick Your own .org site is a great resource for finding the canneries in your part of the country; there are also links for Canada and a placeholder for United Kingdom links, but the former is sparse and the latter non-existent (hint, hint, nudge, nudge to people in Canada or UK)
Got the WWII poster image from Eat Local Challenge blog (the image, for some reason, hotlinks to Life Begins at 30).