"Every contractor we talk to tells us its a great idea and they would pay for leads, but we have yet to have anyone actually purchase a subscription to our site."

This seems like an obvious question, but have you explicitly asked them to give you money for the service? If not, then that is 100% the first place to start, bar none.

If they say no, then there are a few things you can do to help your cause. One is called reversing risk, which more or less means structuring your 'ask' in such a way that you are taking on a risk rather than the customer. In your case, the concept might be mean asking for a refundable 3 month service deposit.

Sales and marketing is where most of my experience lies, specifically in helping startups to find product market fit. Honestly, that is likely where you are having problems.

I would like to talk with you, so I will give you a clarity $20 promo credit to get us started and see if there is a good fit. If you are interested, send me a message.