The June 30 game is in New York. Don't accidentally go to Tampa!

StubHub is for tickets that people need to resell, so it's hit and miss. Your most reliable source is the Yankees' own website. Those tickets are not yet on sale.

It is unlikely the game would sell out in New York. It's a weeknight game and the Rays are not a big draw there (the Yankees are a big draw in Tampa/St, Pete, though - their spring training camp is in that area, so they have a lot of local Florida fans).