A co-op is an asset like any other piece of real estate except you are not really buying the property. A co-op is not condo. When you buy a condo you are buying the actual site (like a house). In a co-op, or cooperative, you are buying shares of a corporation (which is leasing you back the place where you will live). It is a North-Eastern phenomenon that made ownership affordable. So the process is like buying a house, except usually you must get approved by your fellow share holders (the Board).
They both are assets. They both can be bought and sold. Condos are generally more expensive for a variety of reasons. If you need help buying. Click this link. http://www.askrey.net/blogs/rey_hollingsworth_falu/archive/2
-Rey Hollingsworth Falu
Licensed Associate Real Estate Broker