When shopping for a new bike, test ride expensive models of the type you want to buy, road, mountain or whatever. The differences are more dramatic among higher performance bikes, as opposed to path-riding comfort bikes, but even there you might find some nice refinements up the price range.
Ride the good ones first and then ride the ones that cost what you were planning to spend. You may find you only have to move up a model or two to get a bike that feels much more like the top-end model. Or you may decide the one at your original price point is sufficient. But test riding is free, so check out the good stuff.