Not all product-based businesses are also manufacturers. In fact, many online brands buy everything from wholesale suppliers 

wholesale marketplace – whether physical or online – is a platform where retailers can easily find a variety of products from a number of different wholesale suppliers.

Small batch or presale before you buy. These suppliers sell products in bulk at affordable prices so direct-to-consumer brands can brand it, add a markup, and sell it for a profit. 

Wholesale- the case of wholesale, you purchase the inventory from the supplier, So while you control more of the logistics and customer experience in wholesale

Dropshipping- more hands-off approach., you leave this up to the supplier in the dropshipping model. Essentially, a customer makes a purchase from you, but the supplier picks, packs, and ships it. You never buy the inventory from them in the first place, and they are responsible for storing merchandise. This is also less risk, though margins are typically lower. 

Affiliate- marketing involves referring a product or service by sharing it on a blog, social media platform, podcast, or website. The affiliate earns a commission each time someone makes a purchase through the unique link associated with their recommendation. ... You get paid a commission. Great for low no budget 

Inventory.