Making sure that volunteers are properly prepared and not arriving as a volunteer to a program in a host country being a financial burden to them, costs money.
Ensuring that wherever volunteers stay is locally owned accommodation therefore contributing the to the economy of that area is an important part of the volunteering process.
Often organizations that send volunteers over for free haven’t taken enough care to make sure that it is an effective and worthwhile placement. Some organizations may even be sending their volunteers over as free labour which is in reality harming the local economy and putting the local people out of work.