Custom Decals

I am looking to design my own decal for a train. Has anyone done this or have any idea where to go for this. I haven't really looked into too much yet, but I went to the local hobby shop and he has a friend that he thinks would be able to do that for me. There are two different decals I want to design and it doesn't really seem to be cost effective to have it printed. I would want two of each of them, and I can really only find people that will do mass quantities. My thought process is currently changing and I am thinking that maybe it would be cheaper for me to find the decal paper, design it and go to staples and have them print it out.

any thoughts

oh, and the reason that I am looking to do this, is that I have two different close friends that own their own companies and I had at one time worked for them. I would like to get a couple of undecorated cars and make the cars for their companies and run them on my layout.