If your entire business model is such that you can basically force people to use affiliate links, it isn't too bad.

Assuming 1000 piggy banks at $10/week allowance puts your monthly take at 40k. Virtually all of that money eventually gets spent.

At the lowest level of amazon commissions (4%), you're looking at $1600 per month. If you were at the highest level (8.5%), you're at $3400 per month.

It's not awesome at 1000 users, but it pays some bills.