When you have no money to buy an NBA star you have to get (a) role player(s). Like 3 point shooters, rebounders, blockers, etc. They are cheaper. This hint is for NBA 2k7 NOT live '07. This is your decision about who is a blocker or a rebounder, Not the game.
When you get later in the association you have to look for younger people. Most of the young people (28 and down) do not know what they are capable of so they only cost around 5.0 million and down so they are cheap, they have a lot of potential and they are already good. ( Also get them when they are around 76 and up)