You can get a visa on arrival at the poipet border if coming from Bangkok or Thailand. It cost $ 20 for foreigners but the following countries have to get the visa in their respective countries.

  1.  Afghanistan
  2.  Algeria
  3.  Bangladesh
  4.  Iran
  5.  Iraq
  6.  Nigeria
  7.  Pakistan
  8.  Saudi Arabia
  9.  Sri Lanka
  10.  Sudan 

Fairly simple. But if you dont have a photo (4 x 3 cm) the immigration officer will charge you 100 baht (no receipts) and take a photo for you. If you have  also a photo (4 x 3 cm) the immigration try to ask you for 100 baht anyways as they have your passport you have to give the money (no receipt). Those are the facts.

Next scam is is when you are taking a taxi to the Siem Reap. Take a taxi share taxi if you are alone. If not, better take a taxi negotiate the price @ $ 25. They will stop 2 Km before Siem Reap and give you a lame excuse that taxi's are not allowed near your hotel place. Then a tuk tuk guy will come and say he will take you for free. But SCAM. Dont pay the taxi guy any money and tell if the tuk tuk guy takes you to your hotel, you will pay the tuk tuk guy only. Tuk tuk guy will try to scam you to take the Ankor Wat temple next day in return to the free tuk tuk ride. But that is your choice if you need to take that.

Once you reach your hotel its fairly nice in Cambodia.

Tourist e-visa for Cambodia can be obtained by this link in 3 business days: (20+5+3 USD each visa) : http://evisa.mfaic.gov.kh/ContactInfo....

Print 2 copies of the e-visa and carry with your passport.

There is another website for this e-visa, but they charge 70 USD per visa (http://www.evisa-cambodia.net/)