The only way to fly to Saratov is from Domodedovo Airport in Moscow with Saravia. The flight takes about an hour and a half and can cost approximately 5100 rubles. They fly Yak40 and Yak42 aircraft which have been made in Saratov. Saravia also operates summer seasonal flights from Frankfurt and Hanover.
Flights must usually be booked and paid same day at the airport in cash. Optionally flights can be purchased at TK Primavera, the only DMC in Saratov. Pickup of the tickets is then available at the airport before departure.
Otherwise the best way to get there is by Saratov Rail from Moscow's Pavletsky Station, which takes approximately 15-16 h. The trains operate overnight, departing in the afternoon/evening, arriving in the morning.
Saratov is also accessible via rail from Samara to the north (train 10 hours, 400 km) and Volgograd and Astrakhan to the south. The St. Petersburg-Astrakhan' line passes through Saratov. It takes about 26 hours to travel from St. Petersburg to Saratov on train.
There are also buses between Saratov and many other cities, including Moscow. However, the comfort and value of the rail system over the vast distances involved makes the bus service a comparatively unattractive option.
River cruises down the Volga operate during the summer months (early May to end of September). Dozens of boats operated by different companies run from Moscow to Astrakhan. One way or return cruises may be reserved to/from practically any city along the Volga. Moscow to Astrakhan (one-way) with three daily meals is 15,000 rubles (approximately $500 US). Without meals, approximately 8000-9000 rubles