Thank you for inviting me to bid on your project. I consider it an honour.
However, I have been seeking, and getting, jobs that pay $3.00 per 500 words (although I am continuing to work for only Freelancer employer who pays $1.40 per 300 words.
However, I do enjoy writing, and am interested in working with you. Please do contact me again if you have assignments that pay a comparable rate.