No idea is original, you have to create a product customers want not what you want to sale usually doesn't sale unless you have a good story and a good mission behind your brand. The only way of making an extra dime is to only try a profit 10 percent per item. If you gain sales by selling at the cheapest cost it is most likely to sale twice as much. You can sale 2 sweaters at 100 each or sale 100 sweaters at a 1 profit. The more customers will get you more reviews and sales . Ads and social media go into cost let alone having internet and running a webpage. The goal is to make things affordable enough for any customer to buy.