With little actual business experience, you're going to face an uphill climb with that business idea. I don't mean to discourage you, and there's always a chance you could come up with the Next Big Thing -- there are plenty of successful businesses that started in garages.
Domains are cheap. Hosting is (relatively) cheap. With an IT degree, some open source software and a bit of elbow grease, you could probably come up with software that would do what you want it to do. I don't know that $5K will be enough to really get you going, but it might, depending on how much sweat equity you're willing/able to invest.
The thing is -- and this is where I really
don't mean to discourage you, but you do need to be realistic about this -- there are already a lot of other well-established, well-funded sites doing at least most of the kinds of things you're talking about. There are quite a few stock photo sites, for instance, that allow people to upload and sell their own photos. CDBaby handles CD and MP3 sales for independent musicians pretty well, or if somebody's ambitious, they can apply to be a content provider on iTunes. People can use places like CafePress to create and sell calendars, posters, coffee mugs and more with their photos or artwork on them. There are any number of print-on-demand publishers for those who want to sell books they've written, and probably dozens (or more) sites through which people can sell ebooks and software...
...not to mention that these days it's really not all that hard to set up a store on one's own website to sell things directly.
This is not to say your idea won't work! But you do have some questions to ask yourself:
What are you going to bring to the party that these other options aren't?
What is your USP (Unique Selling Proposition)? That's the thing that makes potential customers like me decide it's a good idea to pay you money to sell our stuff for us instead of doing it ourselves or going through one of these other alternatives. It's what distinguishes you from all the other similar offerings already on the market.
What -- specifically -- about your offering is going to make our lives easier, or make us more sales and profit, than your competition? It's not enough to say you'll do these things. You need to have a good idea of how
Come up with good answers to those and you'll be a lot farther along toward a successful business than most new entrepreneurs.