Getting There & Away
Reykjavík Excursions runs the 'Iceland On Your Own' service between Reykjavík and Geysir, which continues on to Gullfoss and then Akureyri. There's one daily mid-June to early September, leaving at 8am from Reykjavík's BSÍ bus terminal. Fares cost 17,900kr all the way to Akureyri, with around a 30-minute stop at big sights, so you can get off the bus and explore. A one-way fare to Geysir costs 4800kr per person; the journey takes roughly two hours.
Tour companies Reykjavík Excursions, Bus Travel Iceland and Arctic Adventures (among others) do Golden Circle tours, which include a stop at Geysir. Organised tours start from 6750kr per person.