You don't need to spend a lot of money on a pitch gage as they all work well. The more expensive ones may be a little easier but not much. The more proficient you get with helis the more you'll find that you'll just use it to get the settings close initially and fine tune more by the feel of the heli.

That being said I have a Helimax that I carry in my flight box. It works fine and you can find them at Tower and most of the online heli dealers. I also use a Vario gage that works great that I got from Ron Lund at rcheli.com