There are a few ex-USSR countries that don't need visas, but pretty much everyone else does.

The original intent of the invitation/registration system was to keep close tabs on foreigners; now it's just an excuse to charge fees at each step.

I've used www.WayToRussia.net in the US a few times and have had no problems. It was $30 for the invitation, $100 for the visa (US citizen), and express post to/from the San Francisco consulate. I didn't have to go in person. I didn't get expedited service and got it back in 10 days.

US citizens get hit with $100 as reciprocity for the US's $100 visa fee.