I wouldn't offer anything for free, but more than once I have offered a 100% money-back satisfaction guarantee for the first week or two of a new contract. This

I wouldn't offer anything for free, but more than once I have offered a 100% money-back satisfaction guarantee for the first week or two of a new contract. This has helped particularly clients that have not worked with a contractor before. The client is relieved of potential remorse or sunk cost, and I still get paid for all my work.