if you can find it in a shop....
i reckon Ebay is his best bet.
but thats just me.
D:
Buying games off ebay is as awesome as being kicked in the balls by a kickboxer.
DO NOT buy games off ebay.
We recently had a guy here complaining about his copy of HL2 which he bought off ebay did not work.
We all had a good laugh..
There are still loads of bestseller versions of HL out there, not hard to catch at all in a standard store.
At least not in sweden
Edit: Oh right, steam...
I prefer retail tho, boxes are hot