Current price for mineral oil at the local feed store (it's an animal laxative as well as everything else) is around $12/gal. Yes, that's a gallon.
Camellia Oil is good stuff, but ridiculously expensive; running around $15 per 4 oz bottle ($480/gal) at knife store prices. If you already have it, use it by all means. I see its superiority over mineral oil as being the magic that its Japanese, really good knives come from Japan, and so on; but if you don't believe in magic don't waste your money. Using it won't make your knife an ancient katana, nor you a samurai.
Tung oil can be expensive too, depending where you get it. Some commercial tung oils aren't safe to have around food prep surfaces and some are -- but I don't know how to tell which is which. While I wouldn't put anything on a handle which wasn't "food-safe," a handle isn't a food prep surface. Up to you. You can also use Danish wood oil, teak oil, rosewood oil, etc.
Adding beeswax to mineral oil helps to make the oil last longer. Some people think that it makes the wood more resistant to water penetration, but I don't know. Either way, as long as you keep your handles and boards oiled enough to not dry out, it probably doesn't matter. Beeswax helps give a richer color, if you care.
You should oil your handles and boards regularly to keep them stable. I find it aids my memory to oil them whenever I do a full sharpening, which is five or six times a year. If you let your handles dry out, you'll have to oil them several days in a row in order to make sure the oil has fully penetrated and the wood has stabilized. Stability is the goal, not appearance.
If you're going to oil your carbon knife blades before storing them to prevent rust, individually wrap each knife in newspaper, old rags, or something similar as well. That will not only help prevent the oil from drying out, but protect the knives from other sorts of damage. Make sure you the handles are well-oiled before storing too.
Edited by boar_d_laze - 2/17/13 at 10:34am