Compact Ajax Contact Form

I need an ajax contact form for my different sites with the following features: 1. It will have one form that can be put anywhere (not a fixed size but something that can adjust according to the webpage I am putting it in) 2. Form feilds - Name, Phone, Email, Comments (text area), Captcha and submit 3. the form won't reload the entire page. After submit, it would just give a message on the same page that the form is submitted. 4. I need the form in html form so that I can just put the html in my webpage and after submit, it will call the backend file and show the message to the user and email the form content to my specified email along with the submitter's IP address. 5. I don't need the form width or its boxes width fixed (Untill I do it), so that if I put the code into a small html table, it will adjust its size according to that. if I put the code into a large html table then it will appear large I don't need many files, just one frond end html code file and one backend file. it should work on any website by just putting the code and backend file in the server. Budget 30$ or less