Whether or not you're going to be attending San Diego Comic-Con 2016, you can still pre-order Sideshow Collectibles' convention exclusive
R2-D2 Unpainted Prototype. With a regular price of $149.99, if you order ahead of time you can save yourself 19% and score the monochromatic astromech for $120.00, with an option to either pick it up at the con if you are going, or have it shipped. Follow the previous link for more details and an image gallery.