When I started with home SMD manufacturing many years ago, I developed a way of making stencils.
I just cut them on a CNC router, with the stencil material being clear plastic sheet.
The stuff they sell for overhead trasparancies in newsagents works good, and is very quick to cut, just use a new sharp HSS endmill so you dont get melt from a blunt tool.
Clear stencils are better to use than metal ones, obviosuly you can see through them.
And if you are wondering about lifespan, some of my stencils did thousands of products and lasted many years. Solder paste residue simply cleaned off with metho alcohol, no sign of stencil degradation.
So, if you want to make home made stencils cheap and easy, that is how to do it. 
https://www.youtube.com/watch?v=_qklxlJc-04