Craigslist Clone (all functionality, slightly different look)

I need a website with all of the functionality of [login to view URL] but with a slightly different look to the main page. All the functionality needs to be there, but I'd like it to have a slightly different setup and look. I'd like the designer to switch the look if they can. Again, functionality will be the same. Main difference is that all the categories will change and need to be editable in the admin panel. Also, I'd like the main page setup to look slightly different than Craigslist. The site will function exactly the same however but will have a completely different application. I'd also like to have the ability for people to create a user name (optional) and for me to put google adwords or other ads up in the future if I decide to. I'll work with you get you a list of the items that will take the place of the US cities, etc on the homepage. The categories within each city will remain the same. I need all the functionality that includes the method of posting (create a post, receive an email to publish the post, user has the control to publish their own posts.) Admin interface should have ability to remove posts, etc. I imagine there are scripts out there that can do this for dirt cheap. I would also need the ability to add new categories and such. I'd also like the site to be a little "prettier" for lack of a better word. Just a little more modern looking, but nothing intense. NO STOLEN SCRIPTS!! I need a site that isn't copied. I need it to be all your own work. If you use scripts you purchased, please be able to assure me that you're using it legally. Will likely go with quickest and lowest bid. Budget around $100 USD and under. Would like to have the site built in about a week or two's time (or sooner if possible). Will pay when site is up and running on my server and bugs are fixed. Thanks.