When I first became Google Ads Certified, I immediately began to wonder how I could use PPC ads to help Karma Sauce. Gene, the companies CEO, gave me a modest marketing budget to do as I pleased, but he warned me not to expect much from PPC. He had already consulted with a number of marketing firms, and they would tell him that there was not much use experimenting with PPC unless you're willing to pour in thousands and thousands of dollars.
There's definitely something to that advice. The fact of the matter is that without a big budget, you're not going to get the quality clicks that lead to direct sales. You'll also have to be comfortable with a certain amount of ambiguity because even with the fairly precise data provided by Google and Facebook, the signal to noise ratio is still high when it comes to determining whether your paid campaign has directly led to a sale. For any business that can't afford to throw money into a pit, that ambiguity can be a difficult pill to swallow.
On the other hand, if you are able to tolerate a degree of uncertainty (and let's face it, you can't really run a business without tolerating it to some degree), there is value in running PPC campaigns. Particularly if you're looking to increase impressions and generate leads for long-term funneling. If you're willing to forego the immediate gratification of a direct sale and play the long game, PPC can be a very useful tool.