Old Chinese Proverb
He who walk trough door side ways ,
With erect Penis
Going to Bangkok

If you are paying for LAOS visa on arrival in dollars
Make sure your bills are in mint condition
Any creases ,tears,any marks on any of the bills
They will be rejected
Guess Laos Imm prefer Thai Baht

Try 9 PY info exchange
Gives you exchange rates for all Thailand banks
By the day
By the hour as it happens
Avoid exchange 1st of the month
Mid week is better