Craigslist-like anonymous email system for Wordpress site.

I have a site that has registered Wordpress users (complete with email) create listings for items for sale. Then, like Craiglist, I'd like buyers to be able to anonymously email the lister to put in an offer to buy the item. The lister will already have an email in the Wordpress database, so that can be accessed as the ultimate destination of the email. However, the buyer should only see an cloaked email (sdfkhsfkjhsdfsd9u78s7f @[login to view URL] kind of a thing). Like Craigslist, that cloaked email should remain anonymous throughout a back-and-forth conversation. In other words, I want what Craigslist has, but with the added caveat of being able to hook into the Wordpress database to fetch the actual email automatically. So I could see a few parts here (written in PHP and MYSQL): 1) When the seller, having logged in, creates a new listing, it should create the cloaked email and someone link it in the database with their actual email. 2) It should save the cloaked email to the listing entry in the db. I can add the script itself into my scripts (I'm decently proficient in PHP/MYSQL, just weak on email-related matters and strapped on time). From what I've seen online, it isn't too complicated, so I'm aiming for a person with high ratings but a relatively low price. Thanks for reading, and let me know any questions you have!