We have the tendency to place value on products/ services/ persons based on a very limited piece of data. We also value things more when they cost more.
One of the most difficult things to decide when selling new products or services: How should it be priced? And also when you have competitors with the same products, there's almost always some margin to play with. On pricing pages with a range of packages, always offer at least one more expensive option than you think your clients would choose. And highlight a 'Best value' or 'Most popular' option to reassure people who're in doubt that they're making the right choice.
Example: Basecamp pricing page:
You can also try withholding products or a service until participants earn the items (new or advanced features). A good example is the 'Private sales' function also seen in the Magento e-commerce platform. Private sales enables shop owners to offer products to an exclusive selection of customers which makes the customers perceive the exclusive offers as more valuable than they might actually be.