The Travelfish details on the Laos border crossings for Huay Xai / Chiang Khong are outdated.
The river crossing is now 40baht, but!!!!
The ticket sellers now impose an extra 10baht for any bag (whatever size) being carried by a farang (foreigner).
So, the full ferry cost is 40baht.
At the Laos border, the immigration staff impose a US1 or 40baht fee. You cannot escape this fee.
If you arrive at the weekend, it is called a 'weekend fee'. If you arrive after 4pm, it is called an 'after hours fee'. If you arrive during a weekday before 4pm, it is called a 'processing fee'.
See also my post re: Chiang Mai to Chiang Khong.
20 April 2009