I have access to a laser cutter, and it is a wonderful thing! However, I've long been unable to use it because I have a difficult time turning my art files into proper vector files. I know people do this every day, but for me any step between completing the projects I'm excited about and actually completing them means I run the risk of not doing anything at all! So while I could do exciting things with a drawing tablet and freely available software, I really needed something I could use on my iPad mini. It's just simpler and it's always with me.
After much research, I discovered that Inkpad would probably fit my needs. I had already tried it out via other very similar copies of the app that were free. All I need is a pen tool and an eraser! The important thing is that it can export files as either svg (vector for the engraving) or as PDFs (For the outer cut lines.) At $3.00, this is the cheapest working app I've found that offers that.
A few hours after downloading it, I had converted my celtic talking board design into a smooth vector file with no pixelation. Besides some technical difficulties involving the computer itself, I was pretty much able to just pull the file up and hit print. It was amazing, compared to the usual frustrating experience with pixelated results!
If you need access to a simple, reliable app that will let you make vector files, I highly recommend Inkpad.