I have not been to Minute Maid Park in over a year, but I noticed that when you buy tickets from Astros.com, that they charge you $15 for parking now. Are there no longer any independent lots open around the stadium which charge $5 or so for parking? Or is the $15 lot through the website the only option?
If you get there early, you can find free parking on the street. Get there right at 6 for a 7 pm first pitch.