In my prior life, before I got seduced away by Uncle Sam, I ran a community garden in a low income community with a large number of Immigrants in the Twin Cities suburbs. It is the one single thing that I miss the most about not being an expat and I am absolutely planning on getting back to gardening when we retire.
How our Minnesota garden, the city donated otherwise junk land (bordered by a gas station, a freeway and an airport) and we charged $20-60 a season to rent the plots, which covered water delivery and tilling. The plots were 20x30 or 20x60. We had a shared compost pile, a shared shed with donated tools, and had some donated seeds from a seed company in the area and shared them amongst members -- because seriously, no one EVER needs an entire package of zucchini seeds! We organized a bulk straw order for mulch once a year. While I was there we added fruit trees along the southern side and ended up doing a honey share arrangement with a local bee keeper, who set up hives on the edge of our garden. It helped us with pollination and him with happy bees. (We got more out of it than he did...)
I had a 20x60 plot every year, and we ended up with more than enough veggies to virtually eliminate the need to buy produce for our family (me, Mr. Marvie, and our boys) and my mom and my sister. I blanched and froze snap beans, peas, kale, grated zucchini, cut peppers, peanuts and cubed squash. We canned tomatoes in all their glory, made jam and apple sauce, pesto, dried herbs, the whole nine yards. It was probably one of the happiest, most satisfying things I have ever done in my life.
Here's a hint on those costs: if you plant things in the actual ground, you don't have to pay for soil, planters, etc. Mulching well with newspaper and straw not only virtually eliminates weeding, but also reduces your watering needs -- which is crucial as a time and effort saver when you're lugging water from a central faucet in 5 gallon buckets! The amount of actual tools you need is pretty limited; like anything, you can certainly buy more, but you don't NEED them. :)
Our hope is that some time soon we'll find The Right Place (TM) and can buy land and start to build up the homestead we eventually want to live in. We've got a plan put together -- we'd like to build a strawbale home, but will start with a camper and some outside projects (Orchard, deck, outdoor cooking space) and improve the place as we go. We'd probably never be completely self-sufficient, because I am not grinding my own flour, dammit. That's a pain. But we'd like to get closer as we go. :)