Travel Agency in Southern Pest

Wasteels

Sells all train tickets, including discounted ones of up to 60% off to those 26 years and under. Next to platform 9 at Keleti train station.
Tourist Information in Southern Pest

Budapest Info

The newest of the half-dozen official Budapest Info offices scattered around town and at the airport.
Post in Southern Pest

Keleti Train Station Post Office

Handy post office branch.