If by contributors you mean volunteers, I don't think you will find a person who would write more than 1-2 articles for free. And that only with the promise that you will get them paid if their work is good. You need to understand that writing is not easy and that's a skill that not many people excel in. If you want quality you need to offer a good compensation.
There is a benefit to contributing to other people's platforms as a writer. You create your own network and gain the ability to provide publication services for other entities. You get an author bio that you can use to position better on Google and to get backlinks. There is a benefit to contributing without a promise to get paid. I get paid by my paying clients, and if I can write to present my opinions to a wider audience I would most definitely appreciate that opportunity.
My main concern with this is that the OP does not have a really good pitch, doesn't explain a lot about his/her website, and if that is rectified I would be looking at writing a nice article for him/her.
