my CSA charged about that much for 10 weeks. And you never really knew what you were going to get. Last spring was cold, and the first two weeks were so bad (we got like, radishes and chives?!!!) that we got two extra weeks at the end of the session. One year we got a plethora of carrots. I didn't mind, because they store well, but others did. Another year we got so many tomatillos that I gave them away to my Hispanic neighbor who started to avoid me because she didn't want them all either.
Thanks to CSA, I learned what to do with Leeks and Rutabagas and Garlic tops. We finally quit this year as we can no longer share the food with our son and his wife because they moved to Canada.
The thing i liked the least about CSA is that sometimes we wasted perfectly good food. We could not eat it all especially if we did any travelling or (God forbid) if we went out to dinner.
ps 20 weeks for $560? that's great!!