Reddit reviews 3mm and 5mm Assorted Clear LED Light Emitting Diodes 5 Colors Pack of 300

Not including the 3d printer or filament, or my soldering iron and other necessary tools:

LEDs: $12.57

Resistor 47ohm: $6.12

Diodes: $5.59

Gateron greens: 17@ $.90/per

ok, I've switched plans to solder an entire system using these LEDs of lower voltage. Now I only ask, will two 1.2 AA batteries be enough to power them and do I need resistors?

That depends on the LED, the battery and the circuit. Let's say you get a low current LED (20 mA - https://www.amazon.com/gp/aw/d/B00UWBJM0Q) and an average 1632 battery (130 mAh - https://www.amazon.com/gp/aw/d/B00102JQIE). That's drawing 20 mA from a 130 mA-hour battery so you just divide. You'll get about 6.5 hours of light from it though probably a bit less since you'll want to size your resistor to allow a bit extra current for a brighter light. You would do better getting a 2032 battery - https://www.amazon.com/gp/aw/d/B00DORK4NE. It's only a little thicker and would give you 225 mAh.

Edit: just realized you posted a link to a product. I have no idea how long that would last but i would guess 6 hours would be an upper limit.

CR2032 Button Batteries and 3 LED Lights per battery taped on to the top/bottom of the discs with Packing Tape.

edit: See through discs work the best (Champion, Proton)