If you are just want to study and learn how to mine bitcoin you can try asic usb i think the cheap cost of usb miner is around 10-20 usd
then you can start usb mining for just study purposes.. Honestly its not profitable right now but if this is for study purposes it can help to learn how to mine..
I would go for the compac as far as learning from a USB miner. It is the most current stick miners, and very good to learn from. I would also suggest getting a RPI to use as a low power controller.
Also with RPI you might learn a little more about commands in mining programs. Also learn about linux. So lots of possibilities of learning if you want them. And if you want small and plug and play there is always R1's. They are pretty much plug in info and they work.
Thanks for your input. I already have rpi2 and will check out for compac USB miners. Is there any tutorials videos or site that you recommend?