I got a stepper working after I bought one with the control interface card. But for my "Dog Treat" system I decided that a linear motor would be most reliable for spitting out dog treats. I bought 2. Here's #1:
Right away, problems. My 28BYJ-40 stepper has 5 wires to the little board. My linear #1 only has 4 wires (blue, yellow,black, red). Will the little interface work? How do I wire it? Ditto for #2 (after I figure out how to solder the tiny contacts).
To get motor #1 to work I bought an "Easy Driver" through Amazon. After the nasty soldering and a couple wrong-headed examples from Googling "arduino stepper..." I got "SparkFun Easy Driver Basic Demo" code & wiring to work.