I got nothin’ on costs, but I can tell you we subscribed to a CSA for a couple of years. For a two-person family it was an unhappy & disheartening experience. The produce was wonderful, but …
Week 1: We get 10 lbs of magnificent turnips, a romaine-lettuce-head-sized bunch of beautiful flavorful fresh-picked basil, and 4 celery heads. We try to eat & give away as much as we can. We eat 5 turnips each, have basil on everything (even breakfast eggs) and get through 1 celery head.
In other words, we consume about 1/4th of the fresh organic goodies from the nice farmer we know & care about. They were far tastier & presumably healthier than the store-bought kind, and we enjoyed making a real production out of cooking & eating, but there’s only so much two people can eat.
Week 2: Farmer sez the basil’s coming in now, so we get three romaines-worth. And 2 lbs of small potatoes, plus 15 lbs of turnips. And 5 celeries & 2 lbs of carrots. We eat as best we can, building recipes around what we got. And we barely eat 20% of it, not to mention the stuff still left over from week 1.
Repeat for another 16 weeks, with the particular veggies & spices changing with the seasons. We got some familiar stuff, and lots of oddballs as well. What to do with 15 lbs of broccoli rabe (which is nothing like broccoli) or 12 lbs of kale, or even 10 lbs of parsnips?
My bottom line: unless you are feeding 10 people 2 or 3 dinner-style meals every day, running a restaurant, or are an avid home canner, the reality is that a CSA is impractical. You get waay waay too much of a couple things, way too much total quantity, and not enough variety compared to what we’re used to. You also cede all control over what you eat to the vagaries of what they planted & when it’s ready for picking.
Finally, because you know the people involved, and how hard they labored to produce each fruit or veg, you feel terrible when you end up pitching 3-week old stuff to make room for next week’s oversupply. So you try to savor each item, be it weird or vastly too much or whatever, and the ultimate reward (in addition to some superb meals) is a guilt trip as the rotting excess parsnips sit there sullenly rebuking you for wasting precious hand-grown food.
The third year we subscribed again, but told him to keep the money & give our food share to a shelter. That felt a lot better.