I take any cutting ruler and put the needle on the 1/4 inch line (well maybe a tad less), line that ruler up so you can place your tape along the edge of the ruler.
For tape I use: plain old scotch tape and sew along it if that's all I have, moleskin (as Geri mentioned), thick two sided tape (I think 3M makes it) (on the top of it I put a scrap of fabric).
I only put this guide onto the area of my machine which is what I'll call the cover to the bobbin area. That way when the bobbin is empty, I don't have to rip off the tape and start over.
I don't like to call myself cheap, but I am frugal. I have the ruler and the moleskin already, and I'd never be able to find the gadgets when I needed to replace things. Just saying.