I am a huge fan of the NFL. My favorite and most expensive hobby is collecting football cards. I wouldn't consider myself to be as outrageous as other card collectors. A lot of people spend thousands of dollars for just one card. I don't go to that much of an extreme.
I started collecting football cards about 4 years ago. I used to just buy the cheap packs. Then I got into spending a little more money for a better pack. When I compared the cards from the cheap pack to the cards from the newer packs, I started to want more of the newer because they were more "flashy" and had better inserts.
Inserts are special cards such as reflectors, autographs, hot rookies and triple threats. Usually the inserts are serial numbered. The lower the number, the more money its worth. Then I started to spend more and more money on cards. I would just buy boxes of 8 or 10 packs. Doing that you have a better chance of getting inserts and authentic materials. Authentic material cards are cards that have a peice of authentic equipment such as a piece of a game worn jersey, a piece of a football, a peice of a shoe or even pieces of the field. Those are some of my favorite cards!
Now that I have done it for years now, my collection is huge and I have tones of insert cards and authentic cards. I also go to sports card shops and buy single cards. I can spend hours and hours in these shops looking at and buying cards.