2 eggs, coffee and toast at the place across the street costs $10 before tax. Which is "cheap" by most standards for us. Our cafeteria has a soda machine vending bottles for $2, water for $1.65 and juices for $2.35. The little sandwiches [which are not healthy for you...] are $4 and cups of freeze dried soup [also unhealthy] are $1.50 ea.
It's a matter of perspective to some degree. Cash shop prices are not reflective of lifestyle or location. It's just $20 for a mount. No matter your disposition.
I lived in Miami before which was cheaper than NYC, San Francisco and Chicago. But we [me + hubby] made a lot less money in Miami than in those other cities. I haven't lived anywhere else to judge what it is like outside of those places.
To a degree it applies to games too. Some countries pay more or less for digital copies. Even though there is like no need to price gouge like Australia over a digital horsey.
The point being, this digital crap is priced as to what people are willing to pay.