Great Question concerning the price of Volunteering Abroad. 
Typically the cost per volunteer depends on the mission abroad. For example, we were lucky enough to raise funds through sponsorship, sites that promote donations, charitable events, etc; Thus our inaugural www.mission2lira.org was really cost effective. Volunteers4Humanity: 
1. Deals with initially Governments, not individuals or facilities. 
2. We depend on the specifications/needs of the Government's hospital/ facility to supply personnel and supplies. 
3. Five day missions. 
4. The organization strives to pay for all expensive while on the ground, thus leaving airfare to the volunteers. However, we try extremely hard to find sponsorship for these fees too. 
5. We are currently trying to secure a mission to the Philippines. Once we receive approval we will post estimated cost per volunteer. We will also assist in raising funds for the associated costs. 
6. The next schedule mission will be in August 2014 to Uganda, however we are currently in touch with multiple countries. Thus check back for relative information. 
You can also email: volunteer@volunteers4humanity.org for more information. :o