Paying people to do things is fine, but probably the most expensive way to get things done. At the end the contributor will not see the money as a reward but as a payment for his work and so request money accordingly.
On the other hand you have lots of volunteers that are contributing their time just because they like to do so. They are the cheapest way to get things done. Maybe with a little money you can reward them in some way, making them feel an important part of the project and the community, happier, and willing to contribute more.
For instance, send T-shirts, stuffed camels or keyrings to people contributing paths, to the best CPAN uploads of the month, etc. For important contributions, you can give better prices as watches, silver or gold pins, etc. or invite them to some conference.
Other possibility is using your influence to help them, for instance, give them some award they can include on their CV or keep a labour exchange website or just a who is who web.