And, yes the fruit is safe once you wash it. For furniture avoid department stores. Your best bets are all the futon and thrift stores along Mass. Ave. in Cambridge. You can even get some nice common area furnishings from places that have repossessed from failing dotcoms. For grocery shopping, there's a store on nearly every corner.
Pricing is almost the same as in any other U.S. city.
However, if you have special dietary need you can shop at Bread and Circus. It's pricey, but carries organic foods. Those who can't or don't like to cook, can settle for the dining hall or eat out. Fanueil Hall is an outdoor shopping area with adjoining historical landmarks and nice sit down seafood and Italian restaurants. However, its sampling of stores is generic.