The USDA Economic Research Service released a report in 2004 called "How Much Do Americans Pay for Fruits and Vegetables?". From the executive summary:
"Among the 154 forms of fruits and vegetables we priced, more than half were estimated to cost 25 cents or less per serving. Consumers can meet the recommendations of three servings of fruits and four servings of vegetables daily for 64 cents. Since this represented only 12 percent of daily food expenditures per person in 1999, consumers still had 88 percent of their food dollar left to purchase the other three food groups. Even low-income households still had 84 percent left.
" The study also found that after adjusting for waste and serving size, 63 percent of fruits and 57 percent of vegetables were least expensive in their fresh form. Even though fresh fruits and vegetables may be less expensive to eat than processed, for many fruits and vegetables the difference in price per serving between the least and most expensive versions was often less than 25 cents. For some, this price difference may be a small price to pay for the conveniences - such as longer shelf life, ease of preparation, and greater availability - associated with processed forms."
Source: Reed, Frazão, Itskowitz, "How Much Do Americans Pay for Fruits and Vegetables?", USDA Economic Research Service, Agriculture Information Bulletin No. (AIB790) 39 pp, July 2004