Murphy is a 3 yr old goldendoodle (in the icon pic he was 1yr old).
We actually took the CGC training some where else last year but didn't take the test.
I signed up for the Delta testing and didn't take the workshop. I knew Murphy was OK at nursing homes (my Mom's) and with kids. Just needed someone else to see it!
At our testing I ended up buying the training book for all the people stuff in it. It's got good info in it. But you can buy it online and home study. I passed the written test without it. Common sense stuff. I had been doing some research though so I must have picked up some knowledge from that. So I ended up paying $20 for the testing and $40 for the book. And then we'll get our patch so of course we need a patch holder, a vest, a scarf/tie for the dog....more expenses but all optional.
I don't think you need a workshop if you dog is trained like for CGC and you know their temperment is suited for it.