I use picture frame mounting tape (it's sticky on both sides). If I need it to be thicker, I use two layers. Also, for the plastic I've used two different things. I bought plastic folders at Sam's Club for another purpose and the clear ones work great for shaker cards. The other thing I've used is the protective plastic taped to the front of my new flat screen computer monitor
(I really am turning into my mother...I save everything since I never know what craft project it might be used in...)