You can look at the same model MoBo even and see it has 2 or 3 different prices depending on what's bundled with it "on board". You might say look at the Rampage II Extreme and crap a brick after seeing it's price.... but a look at the board shows you for example so extras you might not find on other boards, such as :
Daughter sound card
Expanded OC features in BIOS
Advanced Power Regulation
Bundled Connectivity (i.e # SATA ports, USB ports, firewire, RAID etc)
Capacitor type used (anti aging)
Added heat sinks
Built In Fan controllers
Convenience Features like Q-Connector
Actually I'm lost in the sea of motherboards, and knowing nothing, i ask... what does make a motherboard cost 180$ and another 350$? What's the difference? Thanks!
The above posts give you a fairly good idea. I guess you could say it's a similar thing to buying a car. The more you pay, generally, the more features you get in terms of, features comfort, performance, safety, technology and even build quality.
I've always advised that your components should, for the most part match up. Don't buy the latest and greatest processor if you end up sticking it in a poorly manufacturered, low end motherboard. Try to weigh up what you need and match the parts accordingly to your requirements