Hi, there - my name is Amin, came from America.
I've read your brief and can see that you'd like to build a system whereby the supplier can determine when a customer needs oil.
I specialize in full scale of web design & development,
including Drupal , ASP.NET, C#, PHP, Word Press, Joomla, Magento, HTML 5, PSD to HTML, Ajax, Jquery, CSS, JavaScript, Bootstrap, MySQL, SEO, Payment integration.
Based on analysis of requirement and from my experience, I offer $5000 / 45 days.
Milestone steps:
1st - Web design in PSD format.
2nd - Web front end development based on approved app design.
3rd - Web back end completion
4th - Integration of front end and back end.
Of course, my offer is a bit higher than other freelancer's bid, but when you think about the high-quality product for your successful business, I think it's a correct time and reasonable budget.
I will do my best in order to realize your ideas into reality.
Please contact me, I hope to discuss this job more details.
Thanks and best regards, Amin.