I'm Australian, which typically makes me a low risk visa applicant - ie fill out a form, they let you in. Russia, not so. Russia requires a written invitation from a hotel/tour company in Russia to process the visa. Vietnam (where I live) is a high risk country (ie people likely to visit and vanish once they get there), so they needed that as an original. Since I did it all at the last minute, it ended up with a friend in Russia having to race all over town to pay off a tour company to get me the invite letter (purchased for $50), express it to me (over $100), and then process the visa here ($110). Then, on arrival, you have to return to the issuing company for further processing, at which point, another certificate is presented, at a further cost of 950 roubles (about $30 more) and with another two days processing time. It is a giant ass pain to all, compounded by where I live and the speed I needed it done at. Was kind of stressful actually.