depending how much your wanting to spend?
marumi ring light for about 120 on amazon i think
Or you can get rigs e.g. a bar, that you can put an external flash onto to position top left or right of the lens to produce good lighting....I have recently just done this one and so far the results have been good, because you get alot of power, I can get shots at F.32 and get exellent DOF
Or if you just doing indoor stuff you can get a light tent from ebay for about 15 pound, which when used with desk lamps etc will produce a good all round light on the object