You will usually have to post a deposit within a certain time period after making your reservation in order to hold it. The amount can range anywhere from the amount of the first night's rental to 50 percent of the total cost of the stay, depending on your rental agency. While credit cards are universally accepted, double-check with the booking agent to confirm which specific cards are accepted. The balance of the total is expected on arrival. If you cancel before that cutoff time, you'll probably have a choice of either rescheduling your reservation or receiving a refund.
Some places give a full refund, while some keep a nominal administrative fee.
Cancellation within the cutoff period usually results in full forfeiture of the deposit. The same goes for early departure during the time of stay. Most of the agents with whom we spoke, however, did mention that exceptions can sometimes be made if the customer can document a family emergency like death or serious illness.