Buying Sgt Johnston code!

Hey, just getting into ODST and I got it a few days after release without code. I'm looking for a reasonably priced Sgt Johnston code

 

Used mine, but the day ODST came out I checked ebay and they were going pretty cheap, like $7.

Now they are even cheaper. $5-$3 I'm looking at. There is an expiration date on them as well, so may be good to find that out too. Threw mine away so cannot tell you when.

(edit) They expire 1/31/2010