How to make a cheap water heater by my own?

It would help if you told us a few things:-

Electricity / gas / wood burning / diesel

Enough to warm a pint of water to "hand hot" - or enough to run a large house central heating system

Lastly, for "less budget" can you say what less than? £1000, £100 £10 £1 ?

Sorry to be a bit unhelpful, but it really is a bit like me asking you "how much paint should I buy", without giving any more info than that! :)

Mark
January 2009