Pretty sure decals are fine for basic approval. IMO, painting is still the way to go. You can get the templates at trooperbay.com. Best trick I can tell you is to paint it white first then paint it blue. It'll keep the paint from running.
This is one of the things we should look at getting changed on the CRL this year. I didn't have a pack when I got approved so I literally used packing tape to hold it on my chest long enough to take my submission pictures. Luckily I had some time to get my Dirty Boy pack before my first troop though.
I was approved with no pack as well either. I ended up purchasing a Dirty Boy a few months after my approval and now I'm building another. I don't have a lot of money either so it's taken me a while to source things so don't worry about it. Just troop and have fun.