Launching my social network?

[dan]

Hello everyone!
I'm just about finished making my social network. I've basically finished all the programming and I'm getting ready to launch it. I'm not entirely sure how to make it, well, successful (Isn't that what we all want?). I want to make it for my friends and fellow classmates and if they like it then I'll cross that bridge when I get to it. I just want to launch it as something that's cool. I doesn't even have to remain cool for a long time. I want people to be like "Oh, that's that guy who launched a social network from the CS lab." instead of it being a complete embarrassment and people would be like "Oh, that's that idiot who thought his website would be the next Facebook or Google+." I'm not trying to make a Facebook copy (I do have my own cool features). Should I start small with only a few of my friends or should I just put it out there and let society say it's good or bad? I need to know the best way of advertising it. I'm on a tight budget so preferably cheap ways. By the way, this is a solo project. I don't have anyone helping me with programming or marketing strategies.
Thank you Zim and thank you Harris! I would choose a best answer but your answers were equally helpful. I understand the risks I'm taking with this social network (even though it doesn't cost much) because people don't want to leave their friends for another network. I think starting with a few friends is a great idea and I'll see what they think. Thank you for everything!