Hobby Lobby sells a mug that you can use - take it apart and pitch the acrylic shell it comes with. Looks just like kits woodcraft sells, at less than 1/2 the price.
I bought 2 to play with. Note that the chrome ring on the lid comes loose. I epoxied them back on ... better than new.
Big Lots had them in the automotive department, 2 for $6. Remove the screw on the bottom and slide off the acrylic and it looks 100% like the rockler ones.