Hey all, I want to give it a shot at building a 3D printer however because of limited resources, I will be purchasing parts bit by bit. I think I want to start out by purchasing the Stepping Motors and controller. Can someone suggest a good setup that is not too expensive, hopefully something I can get off of Ebay. Thank you.
When i growup i want to be like you. 
That’s how I started out.
I purchased 4 surplus NEMA17 steppers for around $10 each.
Then I bought 4 Pololu drivers somewhere else. Then I scrounged an ATX power supply. I already had an Arduino and breadboard. I loaded Teacup RepRap firmware on the arduino, wired everything up on the breadboard, installed Pronterface software on my laptop. That was enough to let me make all 4 steppers spin under my control.
If you can’t find any of the surplus Nema 17’s. Ultimachine has a great price on Nema 17 steppers. See, https://ultimachine.com/content/kysan-1124090-nema-17-stepper-motor BTW, they also come with 4 pin connectors attached.
While those surplus/recycled stepper motors are tempting, you can get really good NEMA17 steppers WITH a datasheet for about $14. I would never spend more than about $6 each for surplus motors, and I’d still rather go with a $14-18 stepper with known-good specs rather than gambling on one that doesn’t come with a datasheet and may have a strange non-removable mounting bracket and/or non-standard shaft dimensions.
Oh, and when you’re looking at the specs (because you ARE buying one with specs available rather than choosing blindly), don’t just just look at the rated torque, but also at the rated voltage/phase resistance. Sparkfun and Adafruit both sell NEMA17 motors rated for 12V, but because of the way bipolar stepper drivers work, you want your supply voltage to be 3-5x the motor’s rated voltage, so look for 2.4-4V ratings (if voltage rating is not included you can get it by multiplying the current rating and phase resistance).
The Ultimachine motor is a pretty good choice, though the phase resistance is just a bit high for my tastes.
Some of the motors listed claim to be Bipolar, what does that mean? Thank you.
It has to do with the control logic used to drive it. All of the standard reprap electronics use bipolar drivers, so you will need a motor that can be driven in bipolar mode. Both, four- and six-wire motors will work (eight-wire would too, but would be more complicated to wire, and you’re unlikely to find eight-wire NEMA17s), but if you see any five-wire steppers, steer clear, because those are unipolar-only motors (six- and eight-wire steppers can be used in either mode, 4-wire is the easiest to connect, and is bipolar-only).
Thank you.
Take into account that building a printer (especially the first one) can be more expensive than buying a kit. You are paying lots of shipping for small items, and you will make mistakes (like buying the wrong motors).
I should add, before I bought anything I did a crapload of reading and research so I had a pretty good idea what I was buying.
Here’s the motors I’m using.
http://www.mpja.com/mobile/Stepper-Motor-NEMA-17-34V/productinfo/18867%20MS/
And don’t forget to add the value of your time to the total cost calculation.
@Shachar_Weis A good point, but when someone decides to self-source (especially doing it piecemeal over an extended period of time), they’ve usually already decided they’ve got more time than money to spend.
I have built a number of projects over time and it is fun within itself, the waiting, planning, ordering and the excitement of see it all come together. I will take the slow route. Thanks…
Although you usually end up spending more money in the long run doing it that way (especially if you get fed up with the DIY approach and buy a kit after buying half the parts individually, including some wrong ones), you still learn a lot more in the process.
How can we place a price tag on learning?
If the university system can be trusted, very little learning has a ridiculously high price tag. By those standards, you’re getting the bargain of the century.
It’s oft times easier to work fifteen $50 purchases into the budget, over a year, than it is a single $500 purchase.