What are you going to put it on? Boat? Kayak?
Do you mean just DF or one of the products that had DF and GPS too for that much money? For a kayak I like the Eagle DF only for about 80$. For my BC I have a Garmin 546 with big screen df and gps.
Capt John over on Boating forum sells different systems and has extras for the beginner and trick sheets for certain bays. I would suggest you call and talk with him as things change and he has deals on different units. Not to mention that he is a nice guy and will help you.