As an individual who deeply enjoys DnDBeyond I find it  incredibly frustrating and inconsiderate of DnDBeyond to not bother having the price of their goods automatically translate to the users country of origin for pricing to help avoided unnecessary tickets to the help desk and provide accurate pricing for said goods 

Trading in multiple currencies is difficult for many companies. When somebody transacts in a different currency somebody has to pay extra - and it is less for the user than it is for the company. Bigger companies can avoid the fees by having separate payment systems tied to localised bank accounts: for instance, Amazon.com will be USD and they have an account in a US Bank that processes those transactions, while Amazon.co.uk used GBP and has a UK bank account to process those. Localisation of accounts is great for business and customers but requires significant investment and more legal work - as you are literally branching out becoming multiple companies rather than just one. This is beyond the scope of D&D Beyond at this time. Since they won't be doing that and the conversion fees are less for you , and you have more ways to reduce them, it is quite understandable D&D Beyond will just leave it as USD.

As for displaying the price in a different currency they don't process themselves, that would be a bad idea. Currency conversion rates change every single day and even then it would not be inclusive of the actual costs to you as your payment method will charge you. What you get charged depends on many different factors and many people will get charged differently. Then people will complain to D&D Beyond about showing one currency in basket but charging you a different one. It gives off a sneaky underhanded feel. D&D Beyond will then also have to alter the design to be very abundantly clear it is just a conversion tool that might not be correct and is not going to indicate the actual price you pay. Making sure that is and remains clear enough is a hassle - and frankly a legal worry they'd probably prefer not to tango with. 

So it is better in this instance for D&D Beyond to just show USD and let you decide if you want to transact in that currency. By showing it as this you know right away it is a foreign currency and you may have to pay conversion fees. As a consumer you have more options to choose different payment methods and there are other services that may let you negate the fees entirely. If you like to do a lot of banking in different currencies, consider having a chat with your bank in case there is an international card service they could offer. 

So, basically: it isn't simple, and it would be a bad idea.

As said above, currency exchange is a bit messy and it usually is not handled by most businesses. And generally speaking, most international trade is either conducted in USD (or EUR, and to a much lesser extent JPY and GBP), or in the seller's home currency. It is on the onus of the buyer to meet the payment requirements of the seller, not the other way around. If I go to another country and demand their merchants to accept and display their prices in dollars, that would be quite rude.

Yes, but is should at least display that it's in US dollars FFS!

When I look at the marketplace everything is listed as $[amount].

Quote from Lord_Lochinvar >>

Yes, but is should at least display that it's in US dollars FFS!

 
Everything is set to show in USD. If you're seeing different, check that a browser extension of device feature isn't trying to show these differently.

As a EU based customer I must say ddb is the first online store in years where I needed to pay in USD.

So this certainly is not as common as some post above try to make believe.

More so WOTC does on https://dndstore.wizards.com sell in both USD, GBP and EUR. On which they sell bundles that include keys to unlock digital content on DDB.

So I must conclude they have the experience (and probaly the means) to sell this digital content in EUR and GBP that any new business would lack to set this up.

From the customer side, having to pay in USD will cost me not only the change rate, but additionally the extra rate the credit card company/my bank will charge and  extra processing fees. These fees will most certainly be higher that the fees that an international company like WOTC can negotiate. It also means the customer knows the price of the purchase only some time after the purchase. This is not really attractive, right?

So this is a warm invitation to DDB and WOTC to introduce a multi-currency payment method and just charge us with a fee somewhere between what would be the average negotiated fee for the company and what would be the average extra fee the non-US based customer would normally pay. Win-win and happy faces all around :-)