There are some camps within walking distance of Venice-Mestre train station - just across the lagoon where the causeway/bridge takes you. I stayed in one of them once - OK but incredibly packed in in summer at least.

@bilboburgler: I thought Euro was accepted everywhere except UK where it would be in Pounds. No?

The one way fare in case of RV return is around 390 Euros. I am thinking of dropping it and coming back by air or so while the family lazes around for a day.

oops, you're right, @Peter_S_Aus

I was thinking of this one, in Punta Sabbioni:

http://www.marinadivenezia.it/eng/index.php

<< @bilboburgler: I thought Euro was accepted everywhere except UK where it would be in Pounds. No? >>

The Swiss Franc is the official currency in Switzerland. Not every country in Europe uses the Euro; many do not.

To technically answer your question (which Bilbo has already answered), you may find that merchants will accept the Euro but the exchange rate will be in their favor and they can use any exchange rate they want. It most likely will not be close to the standard exchange rate.

An example: If you want a bottle of water from a street stand then the person will probably not accept Euros if it's not the official currency.

Are Euros or other currency accepted in your country?

It is so so easy to change money in Switzerland - every train station does it at near-bank rates and of course banks too - unlike in other countries IME the rates for buying and selling not that great - and there rarely seems, at least at train stations, to be a fee - so I can change as much money as I need as I go along.

Now there are also ATMs of course that charge fees only what your local bank charges.