You really do get what you pay for. It's important to try them in person, especially for ellipticals, which vary in stride length and path and how far apart the pedals are. Go to a large sporting goods store that has a wide variety and try them all. Of the one you like best and feels most comfortable, take note of the type and measurements, and look around for others that are similar.
You can get used ones on craigslist. I am a treadmill girl so I don't have any specific recommendations for you
I bought mine on sale at Sears and they delivered and assembled for me for about $80 which was so totally worth it.