Fantastic Four #52 OW/W CGC 6.5 1st BLACK PANTHER Inhumans app
Get it while it's still affordable. This book (in this grade) sold for as little as $350 just a year ago, and sold for $1,560 in March (Not an Ebay sale).
This is where it all started, 1966, first appearance of Black Panther. Given the success of the movie and the increasing popularity of this character, this book is rapidly increasing in value. I'd hold on to it, but it's time to upgrade.