I ordered one of those last year and I believe I got it at Nancy's Notions for less than 50 cents. I got it for template piecing. I've yet to use it!!

If you take 2 pencils and rubber band them together you get 1/4 inch mark to. i bought the tool you talk about but learned this trick so never used the tool.

You can also use an Add a Quarter ruler for straight lines... won't work for curves. I use my add a quarter ruler all the time :)