Most season tickets require a PSL. My PSL was $5000 per ticket if I remember correctly. If you buy your seat from the cowboys, you can pay 25% down and finance the remainder over 30 years. This enables you to buy season tickets, let me rephrase, requires you to buy season tickets for 30 years.
Some people have since come upon hard times or just want to sell their PSL often for fractions of what they spent. The PSL can be transferred by the cowboys I think for $100. Every year I toy with getting rid of mine or buying another pair.