Experts advise it. In fact, it's been noted that it takes seven pitches to get a sale. In other words, customers need to hear your message over and over - before a percentage will buy. Now, note the percentage might not be big. In fact, it usually never is. Nonetheless, 3 percent of 10,000 people buying a 30 dollar product is still a lot!
Anyway, of course, be sure the product is good, though - and don't forget to "soft sell" (giveaway interesting free stuff etc..).
I agree, but that 'high pitch' you mentioned should be coming from a real big instrument and should sound sweet to your ears. In other words, it's a popular way to sale on social media but the terms and prices should be attractive otherwise the chances are the high pitch would be too high for human ears. You know, human has the ability to hear up to 16000 KHz and that's the reason we don't hear sound emitted by bats. In short, as a marketing professional I suggest we should not go overboard to sell something but keep it simple and user-friendly.
Offering free stuff isn't always the best. If you do it there's a huge chance that people will stop buying your products all together as they think they have a chance to get it for free. This will lead to less active people on your following, etc. and create a community of people only expecting free stuff. Contests, and other forms of things that require them to work for it on the other hand is something that's definitely good to do. This way they know they either have to work for it, or buy it. No free thought in there what so ever.
An email list isn't always going to get repeat customers if you're automatically going to their bulk folder...how is there a workaround for that?