There's two ways to buy a pin. Pick a title you want and track it down. This will cost you more and will likely take longer. IMO you do this when you know for sure a certain title is a keeper.
The other option is to keep your eyes peeled for good deals on interesting titles. Check craigslist every hour(good deals can go in minutes), pinside market, local auction houses, etc. This way can get you a better deal. If your asking what pin to buy you shouldn't be looking for a certain title. Your not going to track down, hold out for and spend more on a certain title because someone you don't know tells you it's their favorite pin are you? There can not be a consensus on a question like this. It just turns into a list of random games.

Now, what should I have for lunch everyone?