I am obsessed with Wilberts. Any time I am going to a baseball game and want cheap food and drinks beforehand, I head to Wilberts every time. Three words: pulled pork nachos. They are the most delicious nachos I have ever had. For about 10 bucks you can get a huge portion of nachos covered in cheese, beans, salsa, and BBQ pulled pork. It's enough to share with 3-4 people (even though you'll want the whole thing for yourself).
They also have $2 domestic beers- always ask for the 16 oz cans as they are the same price as the 12oz cans/bottles. They also have $3 bombs and I believe $4 fireball shots. Then you can walk right over to the field from there!
They don't have the best tvs, so I don't recommend staying here to watch the game, but it's a great place to fill up on cheap beer and food before you head elsewhere. It gets super crowded a couple hours before games until they start, then pretty much clears out.