Definitely check out the Starbucks mugs. The DL mug is only available at the Market House on Main Street ....
Advice I needed about 10 days ago, alas. I had grand plans to make it to Market House and get the "You are Here" DL mug, but lines and crowds and such made it nearly impossible. I should have gotten in the line at Market House the first night because the kids had already gone back to the hotel with DH after PTN and fireworks, but I'd just stood in line at the photo store for probably 30 minutes and then spent another 30 there trying to get Jedi Training Academy photos connected to the rest of my PhotoPass ones. By that time, the second PTN was already taking place and I mostly wanted to get back to the hotel myself rather than stand in line for another 20 minutes. On Sunday we spent most of the day at DCA and only came over to DL in the evening. We ended up leaving just ahead of the parade, but the CMs directed us to the back way behind Main Street so I couldn't duck into Market House without backtracking through the parade crowd and against traffic.
Then on Monday I said I was definitely going to be at Market House for a mug, and also definitely going to the Star Wars Launch Bay because I still hadn't been inside that building (the kids and DH have been there twice, once in 2013 while I was holding a spot for Fantasmic, and this trip while I was holding our curb seats for the parade). However, we'd also expected lighter crowds, so it threw off our plan for the entire day. In Touring Plans, we were supposed to be able to do everything we wanted and be done by 3:30 pm. Reality: between rides breaking down and wait times that were about twice as long as predicted, we didn't do everything on our list and instead gave up at 7:30 pm to go over to DCA, ride Soarin' (which had been closed during EMH due to problems) and then get in line for WOC. I didn't get to Market House and I didn't get to Launch Bay. Instead, I figured I'd just stop at the DD Starbucks on Tuesday morning before our flight...and then and only then discovered that they didn't have the mugs.

Ironically, I'd also had plans to order coffee via the mobile app earlier during our trip and grab it on the way back to the hotel one afternoon, but we were too busy all three of the days to do that. (Tangentially: I'm not quite sure how we survived three very long, busy days at DLR without afternoon coffee, but there you go.)
There is a silver lining: I'd seen the mugs on
Amazon, so I just ordered from there. I'm a little sad that I didn't personally get them at DL, but oh well. Maybe my next visit will allow a little more time for shopping.