Well, it really depends on the company and you should always read the TOS and contact the company if you are unsure. Sometimes, companies offer cheap domain names to entice you into buying their other products (web hosting, software, etc).
When registering a domain name, you should be the legal registrant of that name, giving you the power to do whatever you want with. However, a .com domain name isn't really "resold" like web hosting. It can be transferred from one party to another.
Just a sidenote: The highest price I have seen is $34.99, charged by Network Solutions.