Yes there is a difference. Quality of the briar, quality of stem materials, proper drilling, all of these things can lead to a better smoking experience. The better the drilling, the cooler and drier it can smoke. The better the briar, the sweeter and cooler your tobacco will taste. Now are you guaranteed to get a better pipe if you spend 500 plus, no, there are no guarantees, but the odds are better that you will. You do not even have to spend 500.00 to get a fantastic artisan pipe, there are plenty that go for under 400.00, and in the estate market the deals are amazing. Now of course you can get a really nice pipe for 150.00 brand new but you won't get a hand cut stem, the briar is not hand picked, it can be a great smoker for sure. I recently grabbed a 500.00 pipe that was smoked a couple of times for 139.00 delivered, it is a great smoker and it is real pretty, with really nice straight grain.
When you go for more expensive pipes, looks has a lot to do with the price, the better the grain, the higher the price. There is an old saying that you cannot smoke grain. One of my best smokers is a Mastro De Paja that was a 150.00 or so and I love it. Now it does not have a hand cut stem, which makes it not as comfortable as my artisan pipes, but I would never give it up. I have a really old Upshall that I paid about 80 bucks for that does have a real comfortable vulcanite stem that is a great smoker, but it does not smoke as great as my Rad Davis pipes. There is a difference with a pipe that is made by one guy who knows what he is doing. Until you experience one of those it is hard to understand the differences.