I’m looking to start making my own string but don’t know how to do it or what I need to do it. Note I’m not looking to sell but really just for my own personal use. I would appreciate anything from what materials to use, where to buy them, and any tips y’all have. I also want to make them high quality so that I may sell them if I ever decide to do so.
As an experienced string maker -
The best place to get (most) materials is wawak.com. They have unbelievably low prices (a third of what my local sewing store offers), incredible customer service and incredibly fast shipping. I simply cannot recommend them highly enough.
Best material I can recommend is Maxilock thread. http://www.wawak.com/products/category.cfm/cid/1326/Maxi-Lock-Thread/
It’s the same stuff I use to make the strings I compete with (with a little extra added - but I won’t tell what that is 
)
It’s extremely cheap at about $.04 per string, very soft, and plays very, very well, if you can make the string correctly. It does tend to be a little finicky though… a small change in the production process can make the world of difference between a good string and a bad string. Make sure to fiddle around with your setup to see what works best.
There are plenty of guides floating around the internet. This is the one I started with http://www.instructables.com/id/How-To-Make-Yo-Yo-String/
Here is my guide for improving string rig efficiency, if you’re into that kind of thing. Also it gives some tips on how to make string making easier. http://yoyoexpert.com/forums/index.php/topic,50588.msg498188.html