If you do much driving, you should find road-side stands where people sell the produce they've grown. Just leave the money and take some produce.

There are also some farmer's markets. There's one on Wednesdays from 10 - 2 at at the Kahului Shopping Center. There's another on Fridays at the Center Stage at the Ka'ahumanu Center. There are several in Kihei too. On Mon., Wed & Friday mornings there's one in the Hawaiian Moons Store parking lot and same days in the afternoons there's one on Kihei Road by Suda Store. And on Saturdays there's one from 8-noon at Long's on N. Kihei Road.