This is copy and pasted straight from the wikipedia page for them:

The Diamond Python is typically inoffensive by nature and generally reluctant to bite. These pythons are ambush predators with large territories that often overlap. They move around these seasonally to occupy well camouflaged positions in the warmer months and brumate in the winter months. The females have a range of up to 50 ha (120 acres); males may occupy an area almost twice as large. They are often active during the day and on warm nights, although most of their time is spent waiting in ambush for passing prey. They typically remain in one position for up to two weeks, before moving to another around 100 m (330 ft) away.[3] Morelia spilota spilota kill their food by constricting and suffocating it, and will prey on lizards, birds, and mammals as large as possums. They are not a danger to humans, but are capable of biting and leaving teeth in the wound if severely harassed.[4].

Sorry but I have no idea about the price of Diamond Pythons.