Ipiales is a city close to the Ecuadorian border in Colombia. It is a obligatory stop over on your way to Ecuador. There is nothing much to see except the spectacular Iglesia de las Lajas and the Laguna Verde.
The bus station is a bit out of town, but there are collectivos to the centre.
There are frequent buses from Pasto, Popayan (8hrs) and further north. When you come from Ecuador the border crossing is quite easy and straightforward. The Ecuadorian office is on one side of the bridge and the Colombian Migration is at walking distance on the other side. From here there are collectivos to the bus terminal in Ipiales.
IMPORTANT NOTE FOR BORDER CROSSING TO ECUADOR
As long as the humanitarian crisis in Venezuela lasts, the border crossing is crowded, and crossing the border takes anything from 2 up to 12 houres. As there is only one line for in/out you cannot completely avoid the waiting. However the signs are a bit messy so ask people around where to go with your international transport, if lucky you can avoid waiting in a line with hundreds of Venezuelans, and be in line of Ecuadorians and Colombians.
Colectivos from Ipiales to the border leave from the bus terminal or center (1.700 COP, february 2017) They leave you at the Colombian immigration control. After the formalities in both police controls, a minivan ($0.75c or 2.000 COP, february 2017) or taxi ($3.50 June 2018) in the Ecuadorian side will take you to Tulcán. You can choose to get off at the city center or at the bus terminal.
The Bus company Bolivariano now has a new international route departing Ipiales each Monday (Lunes) at 11:00 A.M. for Lima, Peru. On the top floor of the main building of the Ipiales Bus Terminal (July 2016). Price of a one way ticket is 400,000COP (July 2016), and takes 48 hours. Will not sell a ticket to Quito only.
There are taxis and collectivos just as everywhere else in south America. Collectivos are blue busses (COP 1200 pp) which run around the city, most useful to get to Terminal Terrestre. Furthermore, you can hail small "taxi-like" collectivos which are white and operate just like regular collectivos.
Colectivos which go out of the city (las lajas, the border etc) are white and size of a car or minivan. They leave either from terminal terrestre or the city center. The city center station is On Calle 14, on the corner of Carrera 7. Its on the second block south from the south west corner of Plaza la Pola.
The colourful Saturday Market at the "Plaza Los Mártires", 10 minutes walk from the town center.
Wonderful Jugo bar just off the main Plaza to the north west -- try the Uvillo Completo (COP$3.000, and worth every penny) or the Alfalfa (COP$1.300). The "Completos" are made with home made honey, and the owners are friendly.