Pay-what-you-want schemes can be a useful tool to finance high quality and independent news media without restricting readership, therefore guaranteeing maximum diffusion. We conduct a field experiment with the Italian information site lavoce.info to explore how to structure a campaign in a way that maximises readers' willingness to contribute. We compare messages stressing two possible motivations to contribute, namely the public good component of the news or the importance of the individual contributions. We also test the effect of including information about the tax allowance associated with donations. While the particular motivation stressed does not have a significant impact, information about tax allowances surprisingly reduces overall donations, due to a reduction in the number of (small) donors. Stable unsubscriptions from the newsletter suggest that the campaign does not have an adverse effect on readers.