I used to sell the Boot Light Kits but your link doesn't work so I can't see which one you've seen.. I sold my stock/business venture to someone a short while back and I think he's carried it on on eBay so I think I know what you mean...
It would work out cheaper buying the kit itself because if you were to buy wire, fuses, fuseholders, bulbs etc yourself just for one boot it wouldn't really be worth it.
EDIT: Just found the boot light kits on ebay.. thy only cost £5-6 to throw together but you'd have to buy in bulk (especially with the wire) to get them for that price. It's pretty straightforwards to install a light in the boot anyway, only need an earth, positive, correct rated wire and fuses, and a switch
Edited by yorkshirechris, 09 June 2008 - 11:15 PM.