My friend was discussing arkham horror with me and I told him of a funny situation where another friend missed out on a luck item encounter. It was a luck check to determine whether or not he received anything, his slider on his stats had him set to 0 luck. Now since he was given no rolls at all, could he use a clue token to just add another roll? I was under the impression the clue token was only to re-roll an already failed die roll. Not add another one altogether, ultimately acting like a stat increase. Can anyone help me out? Thanks in advance.

A Clue token adds one die to your dice pool. This is not Elder Sign! The wiki summarises the clue token usage perfectly (http://www.arkhamhorrorwiki.com/Clue):

Assisting on a Skill Check

First, any time you need to make a skill check, you may discard a Clue Token to add an extra die to your roll. You can use as many Clue Tokens as you want on a single check, and you can add them one-at-a-time after you have seen what the roll would be unassisted.

So for instance, if you need to make a Fight check at -2, and you only have Fight 3, then you only get to roll 1 die. So if you roll that die and don’t get a success, then you can discard a Clue token to roll another die. If that one also fails, then you can discard another Clue token to roll another die. And you can keep going until you run out of Clue Tokens or until you succeed.

Also, sometimes you will be in over your head. For instance, you might have Fight 2, and you need to succeed at a Fight -2 check. Well, that would mean that you get to roll zero (0) dice, so obviously you can not succeed. But, you can discard Clue Tokens to add dice to your roll even when you start with zero dice. So Clue Tokens can help you when it would be impossible to succeed on a roll.

Finally, sometimes you are in way, way over your head. For instance, you might have Fight 2, and you need to succeed at a Fight -4 check. Well, that would mean that you get to roll negative two (-2) dice, so obviously you can not succeed. Here, there is an even further advantage to Clue Tokens - any negative number of dice is treated as zero dice, so you can discard a Clue token and still get to roll a die, instead of needing to first burn 2 Clue Tokens "just to get up to zero".

Thanks for clearing that up in grand detail, that clears up a lot of issues I had!