Freelance Designer Tech Recommendations?

Hi, I'm a freelance lighting designer who works with small theaters around town and I'm shopping for some kind of tablet. I want a program where I can basically sketch out the set then duplicate it to take blocking notes during runs. For now I use a regular sketchpad but if I could just copy the set a bunch and scribble all over it that would be much easier. I'm hoping to keep costs low. Does anyone do anything like this and maybe have a program they like for it? I might have to settle for a note app I can also draw on. Anything that isn't me going through more paper.