Historically, these are the cash value of picks.
(adjusted for more recency and balance)

This is a good guide on what to expect to receive or to pay.

picks from 1-1 to 2-15 are not allowed to be sold

pick 2-20  $2,500,000
pick 2-25  $2,250,000
pick 2-30  $2,000,000
pick 3-10  $1,750,000
pick 3-20  $1,500,000
pick 3-30  $1,250,000
pick 4-10  $1,000,000
pick 4-20    $850,000
pick 4-30    $700,000 
pick 5-10    $600,000
pick 5-20    $500,000
pick 5-30    $400,000
pick 6-10    $350,000
pick 6-25    $300,000
pick 7-10    $250,000
pick 7-25    $225,000
pick 8-10    $200,000
pick 8-25    $175,000
pick 9-5     $150,000
pick 9-15    $125,000
pick 9-25    $100,000
pick 10-5     $75,000
pick 10-15    $50,000
remaining     $25,000