Today I want to talk about Nintendo's fabulous cashback program that was overhauled in March 2018. Since the beginning of March, gamers with a linked My Nintendo account automatically receive 5% virtual currency for virtually every purchase made in the Switch eShop. Said virtual currency can be freely applied to virtually any item available in the Switch eShop. Nintendo says that exceptions exist for both earning and spending gold coins, but I haven't come across any yet; they probably only reserved themselves the right to have exceptions.
Nintendo advertises their cashback program with the statement that people who earn lots of gold coins can even get games for free. Sounds amazing, right? While it's true that it can be done that way, it's not the smartest way to go about spending your virtual currency. The crucial thing to know is at which point the 5% cashback triggers, that way you can optimize the process. For every 20 cent (EUR or USD) you spend, you receive 1 gold coin (=1 cent). However, you receive cashback as soon as your spending enters the next threshold. This means the amount you pay in real currency should be X.01, X.21, X.41, X.61 or X.81 (X can be any full EUR or USD), because those five values sit at the very bottom of a new threshold. If you pay 0.81 in real currency, you'll receive 5 gold coins, so the 81st cent you pay in this example constitutes a 100% cashback.
You are looking at a 1.99 game and have exactly 100 gold coins in your virtual wallet. You decide to spend all of your gold coins, so you spend 0.99 in real currency and 1.00 in virtual currency. You receive a cashback of 5 gold coins for spending 0.99 in real money.
Same 1.99 game, same 100 gold coins. However, this time you spend only 98 of your gold coins, so you spend 1.01 in real currency and 0.98 in virtual currency. You receive a cashback of 6 gold coins, so your virtual wallet now contains 8 gold coins instead of only 5.
Obviously, you still need to account for the additional 2 cents of real money you spent, so it's only right to substract that from the amount you have in the virtual wallet. 8-2=6, so an optimized process of gold coin spending nets you 1 cent.
If you buy dozens or hundreds of digital games/DLC items over the course of Switch's lifetime, it will amount to something. It's not much, but it's a process that takes no real effort, so why not do it?
"Wait, gold coins expire?"
Yes, after 12 months. But Nintendo's system is automated and uses your oldest gold coins at any given time, so if you keep spending gold coins on every digital purchase - and you should because of the method outlined above - you'll never run the risk of having them expire. Just make sure to hold on to a minimum of 19 gold coins, that way you can always exploit Nintendo.