This one comes with the adapter. It is $19.99 in store (and online). If you buy in store and you use Chase Pay, you'll knock the price down to $17.99 (10% cash back for using Chase Pay).
Not the BEST price ever, but it'll work for some. I see it was $15.49 in late November right before Black Friday. Fry's had it for $14 with their e-mailed code at the same time.