Going blonde for Halloween, best method?

 

I've never colored my hair before in my life, but this Halloween my friends and I are planning to do coordinated costumes from the Watchmen movie. My role is Ozymandias, and his hair is a medium shade of blonde. This is what he looks like in the movie:

 

 

 

My hair is a very dark brown, and if it ends up looking halfway decent I might even consider keeping it for a while. Here's a pic of me right now:

 

 

 

So how should I go about this? My friends have suggested to just get a cheap can of spray on hair color, but will that look any good at all? I would like to save as much money as possible, but I'm willing to spend a little bit extra for quality. Basically, I want to go as cheap as possible without it LOOKING cheap. Should I get the spray on, or get it done professionally? If I go for the latter, what should I ask for? And also, if I don't get something as temporary as the spray on stuff, I want to make sure my hair doesn't look like crap in a couple weeks when it starts to grow out. Keep in mind this is all brand new to me. Oh and I'm not sure if it goes without saying, but I'll also need to take care of my eyebrows too.