Welcome to the forum. It's good to know that we are an antidote to boredom...
You'll enjoy our FAQ document. It's a useful reference and should give you a few hours of interesting reading.
http://forum.lugerforum.com/showthread.php?t=13121
It's not so much that Lugers are expensive... The problem is that it's easy to make a mistake and pay way too much for one if you don't have adequate background.
There is a difference between a collectible Luger and one that you would buy to shoot. The price difference can be 50%. There are also some more rare variations of Lugers, and the potential that someone has "boosted" and faked the markings or characteristics. More than most firearms, you have to be careful.
There are good reference books that help, but they are expensive compared to other books. Hopefully our free FAQ can help you get started. The value is much higher than the price.
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Igitur si vis pacem, para bellum -
- Therefore if you want peace, prepare for war.