Hello sir,
First of all, I would like to thank you for your attention to this proposal. Knowing that there are many options out there, I appreciate your interest and time, which I don't take for granted.
I am very interested in your job posting.
As a full-time freelancer, I am in the business of making people and companies succeed, so your satisfaction and providing you with an outstanding service are my main priority at all times. Note that my offered rate is negotiable, so feel free to contact me to see if we can reach a compromise that works for the both of us.
Please provide more information about the project and tasks you have in mind, so I could understand and estimate the scope of work.
Regards.