Georgetown is walkable in the centre but sprawling enough that you will need transport for anything further out. The two options are minibuses and taxis.
Minibuses run numbered routes across the city for a few hundred Guyana dollars and stop on demand. They are crowded, and not recommended after dark, particularly for solo travellers.
Taxis
Almost every taxi here is unmetered, so the rule is the same as everywhere along this coast: agree the fare before you get in, and prefer a car your hotel called over one you flagged down, especially at night. LehWeRide is the one operator publishing an actual meter tariff, and GuyWay the one publishing a per-kilometre rate card — between them they are the easiest way to know what a ride should cost before you take it.
From the airport
Cheddi Jagan is 40 km south of the city: 45 to 55 minutes off peak, up to seventy in traffic. The airport runs its own official taxi service and says plainly that arriving passengers should use it rather than anyone who approaches them inside the terminal — cream shirt jacks, black trousers, official badges, and a duty office number to call if something goes wrong. Fares from the rank are negotiated and generally land around 10,000 Guyana dollars, which is roughly what the app operators publish; the premium on booking ahead buys you a fixed price and a tracked car instead of a negotiation at midnight. Ogle, on the eastern edge of the city, is a 3,000 to 4,000 dollar ride.
Going south
The Georgetown to Lethem run is its own world: about 545 km, of which only the first hundred to Linden is paved, and twelve to eighteen hours overnight in a minibus or 4×4 for around 45 to 60 US dollars. None of it is bookable online — you find the operator on Facebook or at the bus park, call, and turn up around five for a departure that happens nearer seven. Linden is the last reliable fuel, cash machine and supermarket before the interior. Flying Ogle to Lethem takes ninety minutes and costs 150 to 250 US dollars, and plenty of people fly one way and ride the other.