I've spent a couple of days in Moscow, but was traveling with a non-profit organization. I would think the travel agent is not a bad idea for that leg, but find one that has some serious Russia experience. I expect that others here may also be very helpful to you. Bureaucracy still reigns there, and you may need to have some extra rubles to grease the skids when you arrive.

We stayed at Hotel Rossia in Moscow, overlooking Red Square. I don't know what we paid. The room was kind of old traditional european hotel, and the staff was generally grumpy. The dining room has views of St Basils & Red Square, but again service and sanitation is spotty (literally!).

Consider looking at www.frommers.com for lodging and other advice--they specialize in budget travel. Following their recommendation, I got a room a block off the subway and six blocks from the Eiffel tower for $40 a year ago May. It was modest but clean & comfortable. Your priceline angle sounds pretty good if you can pull it off.

Have a great trip!

JP