I'm not sure how giving "tickets" to people would work, but you could probably just stream it on a free service like Justin.tv. Google Hangouts might work as well.
Potentially free with a borrowed iDevice or Android device and Wi-Fi.
I live streamed a funeral a year ago. It was pretty easy. I borrowed an iPad and installed Ustream's app. The church had Wi-Fi, so all I needed to do was create an account on Ustream's website, and they gave me the HTML code to embed the video on the memorial website I made. I used a free account, so I was told there was one or two commercials during the 90 minute broadcast. They removed the free trail for the Pro (100 free hours without ads) just before I signed up, but it looks like they have that option again. Afterwards, I was able to download the original video from Ustream's website, and upload it to the memorial website so people can play it back in the future without seeing ads.