I don’t know who your demographic is, but the best advertising platform that I am currently using is with ease TikTok. I recommend trying to advertise your product via there, and potentially reaching out to someone on Fiverr to make an ad if you don’t believe you have the ability to make them.
With TikTok, I’m getting 12% of people who view my ad to click on my website, 4% of such are converting to sales. These are on roughly 600 dollar campaigns ($10 per 1000 views).
It purely depends on the product you are selling, but you can indeed target the age range of your choice. The best type of ad is one that kind of "hides" itself with normal videos, but you kind of need to have an understanding of how TikTok works to do it successfully (hence why I said maybe go on Fiverr and get someone to do it for you).
I personally target 19-25 year olds and see great success personally.