Bandwidth: To monitor bandwidth, I use a bandwidth throttling module for Apache. I have edited the code also so when someone signs up, it will setup bandwidth throttling for them automatically. On average the site uses between 25-30GB per month.
Script: This site uses CeleronDude's free file hosting script. I am not selling the script, if you want to use it you may download it at CeleronDude.com
There is a newer version out now that has bandwidth checking built in, if you want to convert over to that after purchase feel free to do so.
Hosting: I host this web site on my server which also hosts all of my other web sites, so the server/hosting does not come with it. If you can find a beefy hosting plan offering a lot of diskspace and good amount of bandwidth, you could run this. Or if you prefer a server for it, you can find one pretty cheap. Currently I have my server at ThePlanet in Houston, TX who I love.
Offers starting at: $300
Buy it now price: $500
Payment to be made via PayPal or other service if desired (buyer pays all fees!).