First things first, in the best hosting reseller business, you (a reseller) pay a monthly fee to a web hosting provider to rent some web server space, repackage it according to your brand and sell it to your clients at a higher price.  

In layman’s language, think of it as buying something from a wholesaler and selling it to customers at a retail price. The price difference is your profit. Thus, a traditional concept of sales and marketing but with applicability in the field of web hosting.