How would you go about determining the price of a graded card?
From what I have seen... the BGS is alittle higher valued than PSA. Ill go by saying that I will have a 1993 Fleer Tony Gwynn RC graded. The card books for $15.00. What would the graded effects have on the price of the card.

bgs 10 $
bgs 9.5 $
bgs 9.0 $
bgs 8.5 $

psa 10 $
psa 9.5 $
psa 9.0 $
psa 8.5 $

Any idea's so I can see if "ME" having some cards graded would be worthwhile.
Thank you.