Buy My Reference Packs: https://www.artstation.com/meadmclean/store
All my links: https://linktr.ee/meadmclean
A pretty good miter saw if you're just doing simple stretchers: https://amzn.to/2QH2Hq1 (affiliate)
A cheap and decent speed square: https://amzn.to/2W8mJLp (affiliate)
This video goes through the whole process of making your own top-notch stretcher bar. Part 2 here: http://youtu.be/z78Z4U9yMvQ
Disclaimer: Use power tools at your own risk. Work safely, and read the manuals!