Clicks the link, pays your monies, gets your code in email, listens to the music.

From the fine print:

Get all the music you want with an Apple Music subscription.

Terms and Conditions: Valid only on purchases made in the U.S. from the U.S. iTunes Store or towards an Apple Music subscription. Use requires an active iTunes account & prior acceptance of license & usage terms. Not redeemable for cash, for resale, for shipments outside the U.S. & no refunds or exchanges (except as required by law).

I’m buying one, will edit this post once I have a sense of what happens to my existing subscription.

Update: Seth Weintraub passed along this link to the eBay/PayPal equivalent, if that’s your preference.