craftgrrl | I've looked, but need more help

Ok, I did find a duckie mold for soapcrafting (the melt and pour kind), but I think it's a bit on the pricey side. I have never made anything with soap before in my life, and I wanted to make my mother in law some duck-soap (her fave football team is the Oregon Ducks...get it?).
What I was thinking, could I cut up a rubber duckie and use it as a mold????????? If so, how would I best go about it?
I'm strapped for funds at the moment thanks to medical bills, and her birthday's later this month, so I don't have much time either. Any help would be appreciated.
Oh, and did I understand it right that I can use food coloring for soaps? And can I add vanilla essential oil for fragrance???
Sorry if I sound kinda dense, but I'm trying at least.
Thanks for your help you wonderful peeps.