I'm running a business.
I've used Google AdWords before (when it was affordable - 8-10 years ago I paid $0.10-0.20 per click where maybe one in 100 got me a sale, but a sale was worth about $400 to me, and would often result in repeat business). It was worth it, got me quite some business. A good investment.
Now I'm running a tourism business, and clicks will cost me $1.00-2.00 each - offer lower and I'm not even listed on the tenth page of search results. Maybe 1 in 100 gets me a sale, and a sale is worth about $10-20 each, with little chance of repeat business, that's the nature of tourism. Google AdWords is not worthwhile for me.
I have before found Google to be a great platform for targeted advertising. Based on the search words people put in they target ads quite well - I'm using their ads as well when searching for commercial offerings of something. Unfortunately they have become too expensive for me, small time operator. I have to do with SEO and trying to get more hits from search results, which appears to do the job quite well.
Facebook I am still using, but what most irritates me is that I have nearly 3,000 likes on my page, but when I post something after a few days I have a reach of 100-300 people (according to Facebook). And I get 10-20 likes on my posts - typically 5-10% of the reach gives me a like. That's very high, and more likes and other interactions should get a post to be distributed much further - that's at least what Facebook tells me. Obviously something is not right here.
I tried to pay for more exposure, with limited success. I'm targeting the English speaking population of Hong Kong, but half of that is domestic helper (i.e. has no money to spend), and those are highly over-represented on Facebook to boot. I think I got about my money worth back in sales. Not a too good investment. It did get me quite some exposure but imho the price is too high. I've stopped paying anything to Facebook, especially as they don't even distribute my messages to the people that already told Facebook they want to see it: i.e. everyone that "likes" my page.
Now I use Facebook just to enhance word-of-mouth. After events I post my photos, so people may share it with their friends. I share my event announcements in relevant groups on Facebook, and get quite some exposure that way. I'm not paying them anything any more, it's not worth it. Facebook could be the ultimate platform for targeted advertising, considering how much they know about their users, but they utterly fail in that respect.
I'm perfectly happy to pay for advertising, but only if it delivers. Now I have my product listed on various web sites, which resell tickets to my events, taking their cut of the price when they make a sale. No sale, no cost for me. As an added bonus, those services actually do deliver.