It is quite possible to take public transport to and from the airport. Although this option is cheaper you must bear in mind that you will be having to lug your luggage around, to and from Metro Stations etc and it stops at 24:00.
Best option : if you’re traveling fairly light and want to save money.
To and from the airport, Pulokovo LED ( Formerly Leningrad ) Saint Petersburg International Airport, take bus number 39 or 39E or MiniVan K39 to the nearest Moskovskaya metro station.
Costs 40 Rubles plus 40 rubles for your luggage (I know its weird to pay for luggage, and is only applicable on this route)
You will find the bus stop directly outside the airport departures exit on the ground floor. If you’re in doubt about which bus to take you can ask someone at the airport.
Before your trip just grab a screenshot from Google Maps under “directions” its will give you an easy to follow route with bus numbers. Peace of Mind is having a picture of what to do and which buses to take.
Using an Uber is possible too, there is free wifi at LED so it will involve a bit of trust getting to where you want to go without changing your route mid trip. This is really the only option after 24:00 when there is no public transport available.
The Metro carries around 2,5 Million commuters everyday. Rush hours do apply and often you’ll have to stand . There is a culture of giving up your seat for woman or the elderly .
Metro stations are clearly marketed with an M . Ask a local and the closest station is not too far from where ever you find yourself in Saint Petersburg
Using Uber is probably the most convenient way to get around the city if you don’t want to public transport. Useful after 24:00 when public transport is unavailable.
I recommend using Uber over Taxis initially because you as a newbie to the city won’t know what a reasonable fare is for distances and routes. A friend of mine made the mistake of being over charged for a trip from LED (airport) because he was haggled into a ride without knowing the fare upfront.
Buses or Trams will get you close to where you need to go and operate until 24:00 at Night. Use Google Maps to find bus numbers. You can pay cash on the bus or tram
Loading your Metro Card may save you in the long run but it is quite possible to use cash for the duration of your stay. This form of Transport is super cheap . 35 Rubles per ride in the Machutka (Smaller Bus) 40 Rubles for the electric buses, the same for Trams . You’ll find old trams running along side super modern trams.