This really depends on what exactly you are planing.
The easiest thing to do is to have the needy email their advertisment to you. Then you edit the website. Nothing more is needed than Notepad to start with, but any free (like nvu or others) or paid (like dreamweaver or many others) makes life easier.
But just as well you could create a site like this using any bulletin board or forum software. Some are free, some aren't.
Then all the needy can post their own advertisements. Somehow, I expect most of them will be about viagra, sex, fake Rolexes and equities with 200% profit guaranteed.
Best of luck,
Hello! Good Day!
I have an idea of creating "Free Ads Site" that would contain Advertisements of all categories posted by the needy. What are the resources reqd for me to build up this site. I am new at designing the website. I have chosen this to be the content for my site so as to earn some good traffic. Is it possible for me to create this. What are the subjects I should make my self familiar with. Though not so easy, I shall struggle for it. Please help me.