Drupal Powered Coupon Website Module Questions

I'm trying to create a site similar to buywithme.com which deals with customers buying services from various clients on a website. I was looking through all of the extensive modules and I was wondering if there was anything such as a module that would give a unique receipt and number to a customer who bought item x and at the same time put a list of those customers that bought item x with their name and receipt number in a special database that I can hand back to the client .

I was also looking to a module where people can subscribe to a newsletter specific to their city and have an option to check multiple cities to receive multiple newsletters in the same email.

Thank you for your help. I am totally new and I have a few ideas on how I would like to create this site but I think this alone will help me start.