Business Ideas for kids: How to make $10

I got a gig writing the curriculum for "Kids Entrepreneurs" and I need ideas on how kids can make their first $10; the caveat there is that it should give them an idea about:

* Profitability: it can't be "sell your $100 games or parents' stuff"

* Sourcing: best not be a 1-off

* Scalability: can't be something that doesn't scale well like... mow your neighbors' lawn undercutting professional landscaping companies

I've got down so far"

1. start an informational blog and put AdWords/Affiliate 2. Design and sell stickers online (lame but it builds the concept of BRAND)

That's all I got. ANything else?