I've lived in traditional communities where a barter system actually operates and has operated for centuries. The Tibetans nomads and the Tibetan farmers have for example, for a thousand years or more operated on a barter basis in which the limited number of technologies and the limited number of commodities which are produced all have known exchange values.
A yak is equal to ten sheep for example. The amount of meat that you provide as a nomad, to the farmer to exchange your meat or hides or dairy products for the farmer's barley or flour again has been something which has been established by custom. Barter systems certainly work.
But I also think that John Rundell made a very good point about complexity, and I think the opportunity fora few people to opt out and to create smaller voluntary intentional communities based on some form of barter is certainly an option which is available to a few. But it's very hard to see how it could be a basis for a whole society, and whether most would actually want to swap the complexity of present day life for the simplicity that that would impose on us.
And I don't want to agree with Albert that rural life is idiocy. I think that Marx was wrong and I think that cosmopolitanism has its limits, but at the same time I do think that we can't turn the clock back, we have to go forward.