What's the best way to build this website for little to no money and with limited programing skills?

I’m trying to put together a small community site with the features listed below:

-Secure Login / Private site
-Member Profiles with user ability to modify and attach image
-Small Craig’s list type of job postings section using multiple categories with user ability to create new posts and attach images
-Tagging capability that will allow people to sort all profiles or postings by keyword
-Some way for members to contact each other about postings or projects, but without leaving them exposed to external spam
-Possibly a community events calendar
-Possibly a photo gallery to go along with past community events

Is there a good open source system out there that has most of these features? What would you recommend?

If you think I would be better to go with a system that costs money, which ones and why?

I’ve got a Linux server space to work with, so I’d rather it not be a .net solution. But if there is a good Windows option, let me know and I can consider the hosting element.