US dollar is the currency in the internet and majority of the online transaction are made in US dollar. The conversion rate for 1USD is equivalent to RM3.40 and it is wise to price in USD and the other reason is why do people price in USD because it is an international exchange rate money market.

So if you want to price your book RM20.00 at USD7.00 you can actually mark up the price as most book in US are priced 10USD to  30USD. You can actually upsell your product in the market as most of the products are in this range.