Tickets @ Yankee Stadium

I want to get tickets for the upcoming series in The Bronx. When I checked the MLB app prices, they seemed high. I searched and found a site called UndercoverTourist.com (link to Yankee tix) where seats start under $30USD. MLB app prices start over $60USD.

Has anyone purchased from this site. It seems too good to be true. As well, do you have any other recommendations. (In the past I haven't had success with StubHub, etc.)