auto parts store sell a gambit of flare kits for most makes.
i would go there first. they may have the replacement flares if your lucky. what they will do is show you how they are put on.
if they don't have them, you now know how they work and can either go to a wrecking yard or the dealer if needed and do it yourself!
sounds like a good freind and a philips screw driver is all you need.
check ebay.
http://shop.ebay.com/i.html?_nkw=Toyota+fender+flares
depending on the year, the start singlely around 40 bucks. sets can be had starting at 150+-.
cheers!
92 toy pu 4x4 with flares!