How much data does a youtube video typically use on a cell phone?

well im going to get a 3g messaging phone soon and i want to know how much data a streaming video uses. the typical answer that i get is 'it all depends on the quality that the person used on the video.' I GET IT!!!!!!! and i know it uses alot!!! but i just want to know, within the best approximation, how much 'alot' is. i don't know if 'alot' is a couple megabites, or a couple gigabytes! just give me an example like this: 'within 100 megabytes and 500 megabytes' please, please, PLEASE, don't say 'alot' or 'it depends on the quality of the video.' plus, how much data would an e mail without attachments be, how much would a 4 or 5 minute song without video be (im talking playlist.com how much data per song would it be if you have any idea) thanks!