I do the same as other, I plan out what I buy and try to buy with specials and holidays. I started with the PC about a year ago and then just about a month ago I brought the flex. I like crunching numbers and seeing what I can get for the cheapest price. Also its kind of like what Mook said with the wish list but I do it on paper and make sure to get what I think I need sooner (you need it all once you start).
I was in your same boat before I first brought Adams. I had a cart full of products for about a week and then I decided to buy it and try it out. It really is the best decision you can make, your car is an investment protect!