<map lat="-6.214620000000032" lng="106.84512999999579" zoom="10" view="3" float="right" /> Jakarta is the capital of Indonesia.
From the city centre, take the city train from Stasiun Kota to the Tangerang Line (you have to interchange trains twice, once in "Kampung Bandan" and then again in "Duri"). As of 2014, the price should be around 3000 Rupiah (30 cents) for the transport (additionally you have to pay 5000 Rupiah for the travel card, but you get the money refunded at the station of arrival). From Duri you take the train in direction Tangerang to "Rawa Buaya" station. There you walk 500 meters back along the tracks (you can see, hear, and probably smell the Tol Road Highway in the distance). The Tol Road itself is on an overpass bridge, but there are drive-on ramps in either direction.
If you wanna go to the Airport, you stay on the side of the train station and turn left. You will see a small parallel road leading you closer to the highway. Walk up there until you find an appropriate spot for cars to stop (there should be plenty of space anywhere).
To go in western direction, you first have to pass below the overpass, and on the opposite side you turn right and will find an equivalent parallel road. If you only get a ride going into the city, ask the driver to let you out at the highway intersection with the Tangerang Tol Road, or you simply wait for someone to go in your direction.
Jalan Jaksa is a tourist avenue (close to the city center) with lots of cheap hostels situated on it (price around 3 USD). Note that it might be really hard to find free places in the cheapest accomodations and dorms during certain seasons, because the area gets really crowded by tourists.
By the way, if you go to Jalan Jaksa you should note that the nearest mc donalds (about 500 meters) from there has free internet, with computers that you can use (not just wifi, but actual computers for free use) even without buying anything and for as long as you wish.