I put this company together in a week with two friends, as the "CMO" and designer.
It was hectic, but I did indeed make millions selling homemade Christmas gifts. Okay, not really... but it was a great learning experience.
It was an excellent exercise in:
1) Lean startup design
2) Advertising A/B Testing
3) Digital marketing for e-commerce
4) Content creation strategy
5) Branding and brand presentation
6) Time management (I created the company during exam season... I do not recommend doing that, ever)