Crossing the border from Guatemala to El Salvador can be intimidating so always make sure you get there before dark.
Some locals hang around outside trying to scam tourists by telling them they need to get a stamp – then they charge you $20 to get your passport back. Ignore them – however persistant they are – and head straight into the main building.
La Estancia Hostel is a good place to crash if you have to stay in San Salvador over night (it’s not recommended to travel anywhere after dark). It costs $12 for a dorm and cooked breakfast, wifi and towels are included. Take extra care in this city- it’s notoriously dangerous.