The song that everybody associates with the accordion right away, The Beer Barrel Polka. Now, I play it pretty simply. I start, I'm usually in the key of C for this one with the left hand, and it moves to G occasionally. And I usually start with a G on the right hand. It's up to you how colorful you want to get with it. I like to say simplicity is key with the accordion.
Now, a little bit of The Beer Barrel Polka with both hands.
Just a little simple Beer Barrel Polka.