How much does an online store that sells in multiple currencies need to know about exchange rates? Please take the title with a grain of salt. I couldn't make it short and also implying all that I am about to ask here.

Consider Yen devaluation. Forex traders constantly buy USD and sell JPY, or vice versa, based on news and events in politics and economy, or anticipation of the same.

Devaluation of Yen affects exporters and importers and, while it will have an effect on Japanese consumer, eventually, it is not that people in Japan today buy a sushi for 100 Yen and tomorrow for 102.1 yen, based on movements in USDJPY on Forex.

But what is an online store, that quotes goods both in Bitcoin and, say Ripple (but insert any alternative crypto currency here), to do in this situation? It has to have a fast and reliable access to some exchange current bid and ask and constantly update the prices of goods.

What are, if any, foreseeable solutions to this extra pressure on merchants who accept crypto-currencies? 

How does it affect their customers who, implicitly, have to verify quotes in this or that currency in order to possibly get a better deal?
But what is an online store, that quotes goods both in Bitcoin and, say Ripple (but insert any alternative crypto currency here), to do in this situation? It has to have a fast and reliable access to some exchange current bid and ask and constantly update the prices of goods.


First off, would that really be so bad? I could write a program that polled exchanges, took the median of the exchange rates, and use that to price my goods.

Second, having prices that are slightly different because of changing exchange rates isn't necessarily a bad thing, because it can end up functioning as price discrimination. Price sensitive customers will look up the exchange rates and use the one that is less expensive. Price insensitive customers will use whatever is close at hand.

Because of this, how much you need to know about exchange rates is closely tied to how much your average customer knows.