depending on how much you use it, I would not spend more than $30 on one from Pep Boys. I bought one for about that price and it works fine. Sunco makes it and they make alot of quality automotive stuff. or you can go out and buy a bad a$$ snap on for $200+ just depends on how much crap you want on it and how much you want to spend.
I mean the $65 one over the $30 one? Wouldn't even consider $200. Looks like I'm heading to Michigan this weekend to meet some SERCA folks there at a guy's place to install my shifter, do the engine flush, Mobil 1, MT90, and 17 degrees thing there, so I don't need to buy one just yet. But anyways, continuing discussion...
What ever you do make sure it has a dial back on it. Our cars don't have marks at every deg and with the dial back you can set it exact. If you go to the track and get the 98 oct unleaded race gas they come in handy. I went every week last year and used it 75% of the time to bump up the timming and retard it when I was done. To me its a very valuble tool.