How much does it cost to get a snake and all the stuff it needs?

It's not that simple !... Apart from the physical items needed to provide a safe, secure and roomy enclosure for a snake - you also need to know essential information such as the humidity, temperature ranges, what kind of substrate and cage 'furnishings' to use - as well as the correct food animals (and frequency of feeds) for the species.

Oh - and the name of a reputable vet close to where you live - and someone sensible who will look after it if you go away on holiday !