"Pay-to-Pick" is a game mechanism that I've noticed coming up in a lot of board games lately. It comes in many different variations, but it is essentially a little conveyer belt delivering in-game items, resources, or even actions. Let's just call them items for now though.
At the closest end of the belt, items are generally free or very cheap to purchase. The further back in line, the more expensive those items get. Pretty simple, as I said there are little tweaks in a lot of games.
Small World: $0+(n-1) First item is free, or place one point on each item you skip. Points are then earned by anyone else who buys that item later.
Belle of the Ball: $0+(n-1) There are two lanes to choose from, one that builds sets and one that grants special actions. As with Small World, the first item is free, or you must place a resource on every skipped card. All players begin with the same number of resources, like Eight-Minute Empire. However, it's a closed economy. Those resources will never leave the system and no new resources will ever enter the system.
I'm sure there are other examples in other games I haven't played, too. I could easily see this mechanism modeling the spoilage of perishable goods. Each round, the belt moves one increment forward, removing the first item on track completely. Actually, I've got one idea for a progressive price track that wouldn't need a board, but still has the mix of fixed and dynamic pricing in Suburbia.
Each item costs the total amount indicated by the items ahead of it. So the cost of the far right card would be $0. The card to its left would be $5. The card on the far left would be $8. Just a little idea.
I really like pay-to-pick mechanisms. They have a lot of possible variations, present an interesting decision every turn, allow for long-term strategy, and link risk and reward in a very cool way.