The problem with that is twofold. First, laptops are HORRIBLE gaming machines. Seriously. I wouldn't recommend anything more taxing than a rousing game of Solitaire on any laptop, even the so-called gaming laptops. Otherwise you just dramatically shorten the life of the unit, not to mention upgrade options are severely limited to non-existent, you generally have lower end, lower resolution, displays, cramped keyboards, trackpad for a mouse -- and while you can plug in USB mice and keyboards, if you're going to do that, why not just get a desktop to begin with -- all the heat generated by working the internal components so hard has fewer places to go so just kind of sits there slow baking the internal components, and those components are the stripped down mobile versions while we're on the subject. If you get a powerful laptop you either get a very heavy laptop or one that you'll never be able to use off AC power for more than a couple of minutes, the thing will sound like a jet engine at takeoff with all those tiny fans working at high RPMs trying to clear out some of that hot air inside the case, and probably a dozen more reasons I'm forgetting.
The second major problem, however, is that games like WoW are online games. So your Internet connection will likely play a much more significant role in the amount of lag you experience compared to the specs of your laptop. If you're trying to play WoW on a dialup connection, you could have a computer that is 1,000X better than the recommended specs for the game, and it will still lag because of that dialup Internet connection. Same goes for if you're on a wifi connection with a bunch of other people.
That all being said, if you want to disregard everything I said about why laptops make for poor gaming platforms, keep in mind that laptops are basically WYSIWYG. You might be able to upgrade the HDD and the RAM to some degree, but that's pretty much all. So the laptop you buy is the laptop you are stuck with for the duration. Get as much laptop as you can reasonably afford if you plan to keep the thing for more than a year or so. I always recommend avoiding the bargain basement laptops because they tend to be very poorly constructed with every possible corner cut to try and eek out some kind of profit on the unit. The higher end ($2,000+) generally have a healthy profit margin already, so more time and care is put into the construction of the unit. It's not a universal, but you have a significantly higher chance. If you take a laptop that was a high end unit a year or two ago, and now the specs are similar to the bargain basement level laptops, I would still put my money on the old laptop outliving the new laptops. Don't break the bank or anything, but do get as much laptop as you can reasonably afford. If you take absolutely nothing else away from anything I've said, let it be that.
I'm a newbie with computers. I want to get a laptop where I can play games where it doesn't lag. Can I get a good one for about 1700 dollars or maybe a good one that is much cheaper like for 500 dollars? Basically I want a laptop where I play a game like world of Warcraft where it doesn't lag.