The cashew is a kidney shaped nut that grows out of the bottom of the cashew apple. The nut must be heated before it can be eaten. The cashew nut is quite high in fat, about 48%. You can purchase cashew nuts raw, or roasted, with or without salt. Because the cashew nuts tend to be expensive you can purchase the nuts either whole, or more economically, in pieces. Given the high fat content the nuts are most healthful when eaten raw.
Cashews are an excellent snack food in small amounts (high in calories). Additionally the nuts can be used whole or ground in desserts, or topping for salads.
Whole Foods Markets sell whole cashews and cashew pieces (raw or roasted) in their bulk foods department. Trader Joe's sells raw and roasted cashews, whole and pieces for a reasonable price. The most expensive way to buy cashews would be small cans containing roasted and salted nuts. Of course you can always purchase cashew nuts online at Amazon.com in bulk or smaller packaging.