Strategy: "Offer a brick to win a gem"

This is also one of the original 36 Chinese stratagems.

The idea is very simple - offer something of lesser value ("the brick") to gain something of higher value ("the gem").
I would say that this is probably one of the most used strategies.
"The brick" may be of real or illusionary value and may come in many forms - e.g. power, wealth, sex. When somebody flirts with the person in power trying to get him to do something, or tells him that "I could do this or that for you" - it is essentially "offer a brick to win a gem" in action.
It does not have to be an illusionary "bait" - the value may be very real. When store owners offer sales and discounts - they offer a little price reduction to get the profit or to get back the money invested in the "stale" product. Same thing when they offer to pay in many installments.
With kids - actually every time when you say "if you do this, you will get that" - using a "reward" - you use the "offer a brick to win a gem" strategy.
The simple applications of the strategy may look straightforward and maybe unexciting , but it may be used to reach the goal very effectively and in more sophisticated ways. As in the following examples:

Examples:
1. Apple stores, Drugstore Wars
2. Office Depot