Libya is expensive, and travellers intending to go shopping will be tempted to change their money in the black market before starting to negotiate with the vendors, or even pay directly in dollars. In such cases, Libya is no longer expensive, but before attempting this, you should know that this is illegal, and involves a certain risk.
Handicrafts are differing from region to region, but there are cases of imported stuff being sold as if it was Libyan (imported handicrafts are often by far cheaper). Most of the time, the most interesting handicrafts seen by the visitor's eyes, are Bedouin handicrafts, which often are quite crude in its style, indicating the often traditional and primitive conditions under which they have been produced. Rugs and wraps, as well as pottery is most recommended.
Of things to bring with you, film for the camera is recommended. Film can of course be bought, but it is far more expensive than in most Western countries, and you will often have problems finding your brand, thanks to the ongoing embargo of Libya.