Someone is making really nice handmade jewelry (bracelets/earrings) that sell for $15-$40 a piece. How would you get their sales up to hundreds of pieces a month without spending much money upfront?
The problem here is that it is handmade. In order to scale to hundreds of pieces per month you will have to scale up the labor. One person can only do that for so long before he/she quits out of exhaustion. You will also need to invest in marketing because jewelry is something that is sold on the vanity of the product and not its quality. I'd say it would be better to concentrate of marketing it first, without looking at scaling to hundreds of sales.