So now that iTunes variable pricing is live, cross-shopping with Amazon is going to be a Thing -- and while we're certain slicker utilities will pop up soon, for right now we'd install Advantageous, which is just a little script that automates an Amazon search query from within iTunes. Yeah, it's not perfect -- it fails if you're logged in with iTunes store credit and it's far from bulletproof otherwise -- but it's a fine way to at least have kids or the less computer-savvy stop and check prices with at least one competitor before laying down an extra thirty cents on each purchase. This is has been a public service announcement... with guitars.
[Thanks to everyone who sent this in]
Read - Advantageous for Windows
Read - Advantageous for Mac