If we are being honest, fair value for free play is probably about 90%.  I know the AP's don't like that because they want to get more value.....that is their job as an AP. 
 
@ 90%, it is still +EV, but may not be worth the time and effort depending on amount.  I am not going to buy $50 free play @ 90%, but I would probably buy $2000 free play @ 90%. 
