If you haven't been picking these up as they're announced, Amazon decided to finally give you a way to get all 25 with one click over at their 25 Days of Free page (amazon.com) - scroll down past the days to find the checkable list and "Buy selected song" button.
Oh, one more thing - if you're GIFTING MP3s, Amazon says that you can get $2 off with the code GIVEMP3S. Details about THAT over here.
THE TOP SELLERS 1. Order of the Black (The W at Amazon) Black Label Society (E1 Music) 2. All About Tonight Blake Shelton (Warner Bros.) 3. Camp Rock 2: The Final Jam [Soundtrack] Various Artists (Walt Disney Records) 4.