[Fastball]

I have an original collection of vintage football and baseball cards that I purchased from my dad. I've been wanting to get some of them graded. Many of the '53 and '54 Topps and Bowman are in crisp NM-MT condition. Would love to send in 50-100 at this time and at that price point (have hundreds more I'd love to grade but not sure if I can justify and I guess I just don't understand how it works) if these qualify. I had a trained eye look at them once who told me I may have quite a few 7's and 8's. What if one gets graded an 8 or 9, which make them worth more than $100 do they end up charging you more?