Originally Posted by
SQFreak
I used that too, but they wouldn't sell me the SIM at Domodedovo or at the store until my visa was registered. Once my visa was registered, and after some rather incredulous due to the fact that my passport was issued at the New Orleans Passport Agency (it was a few months after Katrina), the MegaFon store at Okhotny Ryad sold me a SIM.
The top-up time is dependent upon how much you put on it at a time, if I recall.
I had the same issue when I was in Russia. I had to provide my passport with visa and migration card to purchase a SIM card (I got MegaFon I think). The store did accept copies of the documents after a bit of discussion (none of which worked in English so knowledge of Russian helped a lot)
Some of the people I was in the country with purchased their phones (they did not have tri- or quad-band phones) at a рынок (market) or a street vendor and did not have to provide any documents. They were really surprised when I had to provide my passport.
A sim card purchased local is the cheapest option. Topping up can be done at many places through automated kiosks. I picked up an "international" sim card for when I traveled outside of Russia that had an Estonian number but it was much more expensive and ridiculously expensive to use when I was in Estonia--I think it was €1 or €2 per minute, but had free incoming so it did come in handy when people called me. I picked a cheap quad-band phone from eBay so I did not have to worry about losing or breaking it.