Rent Subhuman (2004)

Martin Romero is hit by a car, and the driver and his girlfriend decide to take him back to their place. Through a turn of events, they come to discover that Martin is a very troubled man. Wanting out of their home, they agree to collect the drugs needed to heal his wounds. Through the people they come in to contact with while purchasing the drugs they come to understand Martin is a very sick man who needs help: and that they are in terrible danger...