I've been in Colombia for exactly 89 days and during this time I've had cell phone service with a company called Tigo. It's a prepaid service with no contract that costs like 35,000 Pesos (~$18 U.S.) per month and includes approximately 100 minutes and 2GB of data. The data connection is relatively slow (because it's using the old-fashioned Edge network system instead of the newer 3G or 4G networks that we're more familiar with now) but coverage has been pretty good as I've only been in a couple of places where I didn't have service. Overall, as a relatively cheap connection to the outside world, I give it one thumbs-up for the (relatively) large data allowance, which is important to me.
What I haven't been as excited about are the (at least) 73 spam text messages that Tigo's sent to me in the 80 days that I've had the service. It's almost one per day but there have been days where I've gotten like three different messages. They're usually asking me to add minutes or text service by responding some code. Nothing too exciting in other words but it still seems like a lot. Oh well, I guess that it's the (low) cost of staying connected!