How does the steam market work for different currencies?

Valve not only rounds to the nearest USD cent in the converted currency, they then also tack on their own fees based on the price. This is also rounded to the nearest cent.

Due to how both of these roundings work, occasionally a market item can be listed out of order when it comes to sorting items by price. That listed price is ultimately what you pay, so both parties get what they agreed to in their own currency.