Here's an interesting article meant as a guide for buying bikes:

http://www.abbysguide.com/bike/guide/where-to-buy.html

You could quote it. I don't know if I would want to include the bit about how it's OK to buy a big box bike if the child will grow out of it quickly.

I also really like Juju's suggestion.

As for purchasing a bike for display or taking photos, it's a good idea but I'd be really careful about stepping on toes. The last thing you want is a corporation like Wally World breathing down your neck.