The company I currently rent dedicated servers from (Swiftway) has a promotion for their CDN service: first 3 months for 1$, 56$ a month after for 2 TB a month of bandwidth. 7 cents per GB after. Link to the offer:
http://www.swiftway.net/offer/cdn-offer/I think it's a very good deal for a content delivery network BUT...
A CDN won't help you with live streaming, it's just for downloads.... and honestly, I don't think you're at that point where you'd have the need for a CDN.
Have a look at the "cloud server" offers here:
http://www.leaseweb.com/en/cloud-hosting/express-cloudEven the 9 euro vps (because basically that's what it is) would be enough for serving the static files to users - the vps comes with 500 GB of bandwidth and 40 GB of disk space and this company is well known and has great datacenter, so the people will have no problems.
For streaming the show, I'd suggest having a look at Voxel.net:
http://voxel.net/voxcloudYou can rent a cloud server by the hour for 0.10$ an hour and pay for bandwidth separately at 0.10$ a GB and their network is awesome (and they add CDN for free, but if you pay for a few hours a week it doesn't help you much).
Your only problem would be the IP changes - I'm not sure how their cloud servers work but I think you can just create the cloud server, use it, stop it, restart it after a week or when you want to use it and you'll pay only for the hours it's online and bandwidth you use... and it's probably going to have the same IP but you have to chat with them to confirm.
You can rent the server an hour or so in advance, set up the streaming server software and after the show