I have one of those card things it gives you 10% more when u sell your games. So lets do the math, 100 in trade, no card is still a 100. 100 with the card gives u 10 bucks more (10% of 100 = 10), so that extra 10 u get only if you have that card. That means thE 15 that your are spending you are getting 10 back, so how…