I realize this question may sound very game-design oriented but it's not. It just hit me while playing a game, got me wondering and is very theoretical and purely for my own research, plus a game design SE will not be able to give me in-depth understanding of how the users possibly think.
If you have a game that uses Gold to say build a building. You can earn the gold trough in-game actions. There's secondary resource - Diamonds, those you can buy with real money 1 diamond = 1 real life dollar.
Lets say that building costs 1000 gold to build. You have only 500 gold.
All of the mobile games I've seen give you the option to substitute X-amount diamonds, say 1 diamond for every 10 gold missing. So you can trade 50 diamonds for the missing 500 gold.
The next building will cost 2000 gold but now you have zero gold and can again translate 200 diamonds for gold. Next time it will cost 10 000 requiring 1000 diamonds, and so on.
Each time the diamonds are less valuable but their in-app purchase price remains the same.
Now to the actual question: If instead of 10-to-1 substitute, a system where 1 diamond represents a percentage missing, say 10% of the purchase no matter how much that is, wouldn't that give the user false sense of him getting a good deal and using more diamonds as they will not lose value over time?
So the first time around you're missing 50% of the required gold, in the new system you'd only spend 5 diamonds. For the second and third building you'd spend total of 20 diamonds.
Instead of the three purchases potentially costing you 1550 dollars and/or your users loosing interest, it would potentially costing them 25$ a price more users are much more likely to pay AND the added benefit of keeping them hooked into the game.
Hope I'm on-topic enough.
