It's no coincidence that most coin collectors from my generation (baby boomers, just in case you didn't know that about me) became enamored with numismatics during the 1950s and 60s, when you could still find premium coins in change. Our hobby is a perpetual treasure hunt. Even today, I rarely enter a bourse room at any coin convention without a tingle of excitement. It seems that the greatest finds pop up when least expected. Like the time a dozen years ago when, at an otherwise ho-hum convention, I plucked from the inventory of one of America's shrewdest and most successful dealers a pair of obvious specimen proof 1927 nickels - marked gem uncirculated and a few hundred dollars apiece. The dealer betrayed some surprise when I paid his price for the coins, which were marked about 50% over the going price for gems. Nobody believed such specimens even existed. Since that time, several more have shown up, and these spectacular coins, which have been verified as proof/specimens by both of the major grading services, easily command five figures.
Try finding a deal like that on eBay!

I hasten to add that if the nickels had been well-known rarities at the time and simply mis-marked - perhaps a zero or two omitted from the price - or had they been offered to me by a neophyte or a collector rather than a dealer, I would have been compelled to offer a much higher amount for them, as I often have in similar circumstances. But fortunately for me, the rules of the game permitted me to take advantage of superior knowledge over a fellow professional, and I suspect that that particular dealer has managed to "pick me off" a time or two as well.

I guess my real point here is that, the Internet notwithstanding, if you're not attending coin shows you are missing one of the greatest experiences the hobby has to offer.

In my opinion, the definition of a great collector is someone who can recognize opportunity and knows when to take advantage of it. Such collectors are not limited to those seeking rarities. For someone assembling a set of VF grade Lincoln Cents, the find of the day might be a well struck 1924-S with perfect, light-brown color. Within reason, the chance to own and enjoy such a scarce (and reasonably priced) coin is worth far more than the price usually paid.

Knowing when to pay "too much" can only be gained from research and experience. Experience comes from immersion, which in the case of numismatists means looking at coins "in the flesh". Yet even the most experienced and astute numismatists will seek the opinion of experts prior to making a significant purchase. The best place to find coins and experts in abundance is at major coin conventions. When time permits, most dealers and collectors are more than willing to share knowledge and offer opinions. I'm not suggesting that you ever depend solely on other people's judgment about how to spend your money, but a second, or even third opinion, can be invaluable. Talking to experts, and viewing a lot of coins in person, are great ways to help you rapidly become a great collector.