In Fantasy Challenge mode, two great and cheap players are Mike Alstott (FB) and Antrell Rolle (CB). Rolle has great catching and it is almost a guaranteed interception in every game that he plays. You should get the cheapest players at every position, then save it. Go to "Rosters" under "Features" at the main menu and increase your players to a 99 overall. Doing this will make your team cheap and outstanding. Also, no one will be able to negotiate your players away.