Hi,
I have gone through your requirements and I can calculate the distance between two places using Google Distance matrix api. I believe the amount should be calculated based on base location and destination post code.
Though destination location can be found using google geocoding service, It won't be entirely accurate and so distance can't be calculated properly. I would suggest to use google autocomplete box (found in google maps to find directions source and destination textbox) to enter destination location or landmark near to it from which distance can be calculated more accurately.
But if your requirement is it should be postcode, it can be done with the above said limitation
Pls PM me to discuss further details.
I have 3+ years of front-end devlopment using HTML, CSS, JS, jQuery, Bootstrap and AngualarJS. I am proficient programmer in asp.net and php also. I can assure you that I will provide quality work in given time period without any issues. The final code will be delivered with comments and documentation.
Looking forward to work with you,
Kasi