Please take advice from a professional (e.g. an accountant) for implications of multi-currency trading in your locality
Background
A TourCMS account has a base currency. You chose this when you first created your account. Retail (sale) prices are configured in the base currency of your account
Generally, you will sell in this currency. However sometimes you want to sell in other currencies (e.g. you may want to have a USD price, but your account is in Euros)
Solutions
Single sales channel - multi-currency sale prices
In the Euro example, you would sell in Euros, but you could, on initial pages on your website, advertise in multiple currencies. At the point the customer has selected the tour and commenced booking, the price would revert to the sale currency of the channel being used. A good example of a website with this approach is Gray Line
One advantage of this approach is that you can have many sales currencies on your website (to guide customers). Additionally, it keeps your accounting clean as you only are selling in one currency.
This will require some work by your web designer/developer rather than any configuration within TourCMS. Open Exchange Rates provide an affordable source of exchange rate data that they may find useful.
Generally, this is our preferred solution and is one adopted by the larger travel websites.
Multiple sales channels
Within TourCMS you can set up multiple sales channels. Each sales channel can have its own sale currency
Channel A - Sell in USD
Channel B - Sell in EURO
To set this up, first, you need to configure an exchange rate FROM your base currency TO your additional sale currency (This is in configuration & setup).
Then in the channel manager, change the sale currency to the required currency.
A rounding rule can be applied to ensure that, as a result of creating a new sale price, the price is still nicely presented.
Markups can also be adjusted so you could make Euro prices +10% from what the sale price X exchange rate would generally create (There is a specific markup setting rather than altering the exchange rate)
If you are using this approach then a booking engine switch may be useful
Fixed price loading
IF you want to configure prices specifically for a different currency you can configure a sales channel to take the sale price from the configured cost prices.
Channel A - Sell in USD - takes prices from COST prices
Channel B - Sell in EURO - take prices from SALE prices
This does enable you to set a FIXED USD price as well as a FIXED EURO price. Because there are only sale prices and cost prices, this only works if you require 1 additional currency (rather than many currencies)
Additional TourCMS account
TourCMS is not expensive. Do consider having a 2nd or 3rd account if you have a problem that can't be solved by the solutions above.