How to get a visa on arrival in Cambodia

Getting a visa in Cambodia is a really straightforward process.  I tried and failed to obtain one from back home; I contacted the embassy via email and phone, but no-one could help and they didn't even respond to email.

Before boarding the plane in Bangkok there were 3 documents to pick up - see below.

 Arrival/departure card

 Back of arrival/departure card

 Main Visa application form

 Customs & Excise form (front)

Customs & Excise form (back)

Remember to bring one passport photo for the main application form! (They can take this at the airport, but it costs)

The arrival/departure card --> the departure side of this will be torn off and stapled into your passport. 

CAUTION: make sure you definitely get the correct visa, a tourist visa is $30, whereas the business/ordinary (more than 60 days) is $35.  Even if you pay the correct amount they are known for issuing the cheaper tourist one, so be aware of this! You can check it on the stamp in your passport.  Otherwise it means leaving the country (to Bangkok) to renew it.