[natas305]

I haven't gone same day, but I bought a ticket a day or two out to go to Bogota from Medellin for a few days, and it was still super cheap. I think like $70 USD round trip or something. I do remember thinking about going to Cali from Medellin last minute for a few days last month and it was ~$100 round trip. There's pretty good competition between carriers in Colombia and lots of these flights between Bogota and Medellin/Cali/the coast so it's pretty viable, but obviously a little planning in advance should give you better prices if you can do it.