I think you should go to your nearby hardware store and ask them to show you the different shades of blue, preferably one that resembles "candy blue".
I believe they should allow you to spray just a little but so you can see the actual pain color inside the can.
That way you know for sure which blue you are getting.
There are also several precautions and steps you have to take in order to paint your beach cruiser.
If you'd like some help, contact me.
Good luck bud!
Update: I concur with SoccerRef, the thought of a arts and craft store, or local hobby store had totally slipped my mind. I think you should utilize as many sources as you can. Ask around you, look on the internet, the said stores, etc. Sounds like a fun project.