Hi Hector :)
I've gone through your requirement and I believe I have a good understanding about what needs to be accomplished in this project. I might need a slightly more information like when the trigger needs to be fired (i.e. before insert, after insert, before update, after update). Apart from this, the task looks quite straight forward.
I understand that you may have concerns regarding my credibility as I don't have any feedback on my profile nor it highlights any previous projects that I've worked on. It's because this is my first bid and I'm trying to land up with my first project. But I assure you that you will not face any difficulties whatsoever in getting your work done under the given time and budget without compromising on the quality of the work that I'll be providing. I've been working on Salesforce with a Fortune 500 company for quite a time now. I'm well versed with apex triggers, apex classes, salesforce configuration and visualforce pages. I've successfully delivered 3 projects so far while working in my current organization, with all the 3 clients being a part of Fortune 500 family.
If given a chance, I'd be really glad to work with you on this requirement and would be able to deliver it in one complete day. Looking forward to hear from you. Have a good day! :)