If you're using social media for your business and expect sales to just happen because you tell people to buy.. then you probably need to stop wasting your time and money.
The worst way to sell online, especially on social media is to sell. Sounds stupid but selling doesn't have to be hard, don't make it hard for yourself by boosting a shitty facebook post on your page that just says
"We sell product X, buy it today"
At least give people a chance to see the product and what the product is about, to hell with the product just tell them the business story or how the product helps the end user.
Think of the adverts for the apple iPhone that just focus on the images the phone can take "shot on iPhone" doesn't actually show the product at all.
If you have a product or service that works and is great, tell people why it is and then tell them some more, maybe give something away first then tell them more.
Keep it simple, put yourself in the end users shoes and see what happens next.