The primary aim of your business is to transact with customers. The only way transact on the Web is to build trust. Trust is a delicate thing, and it does not survive misinformation or manipulation. Avoid trying to engineer results. Focus instead on providing value and meeting real needs.
Gimmicks like false scarcity are hangers-on from a bygone era. Most people will see through them. This is especially true when you are selling a digital product. Computers are always on, copies are effortlessly produced, and digital bits are never depleted. How could a digital product ever truthfully be scarce?
Scarcity is not always a gimmick. Physical products are sometimes scarce. If your products actually are running low, feel free to point this out. It is doing your customers a service. Those who procrastinate may have a longer wait as more products are procured.
Limited time offers
Artificial limited time offers might work with a couch potato watching late-night QVC, but they won’t budge customers on a typical website. Your online visitors are likely to be proactive and in control of their experience. They will abandon your business as soon as they sense anything duplicitous.
You may object that sale prices sometimes work well, but if you put things on sale too often it establishes the expectation of a discount. Instead, why not price things fairly and focus on the value your products create? If you expect your visitors to become customers and friends, treat them with respect. Give them the truth. Ask them to decide.