I normally spend about 1/3rd of my shopping budget on produce each week. I estimate that the CSA cut these costs by about 30-50%. Using drying and freezing, we are still using produce from this summer in March, and my produce bill remains low; I estimate that overall we will have saved on the order of $400-500 in produce costs. On top of that, the taste and nutritional quality of what we are cooking is far superior to even the best quality store-bought produce.
The time commitment had direct benefits in involving our whole family in growing, harvesting, preparing and eating the food together.