You can get FL here new for 6 pounds:
http://video-games.shop.ebay.co.uk/?_from=R40&_trksid=m38&_nkw=Freelancer&_sacat=1249

Or here used for even lress than 4 pounds:
http://www.amazon.co.uk/s/ref=nb_sb_noss?url=search-alias%3Dvideogames&field-keywords=Freelancer&x=0&y=0

Note: You don’t have to worry much about an used version IMHO, FL doesn’t require a CD key, so there is no chance that someone cheated you about the key.