As an attorney I set these up regularly for foreign-owned small businesses. Top questions I get:

1. Can a foreigner own 100%? Yes.
2. Do I need a Colombian partner? No.
3. What does it cost? ~$1,500 USD all-in for incorporation, opening accounts, RUT.
4. Timeline? 2-3 weeks if you have apostilled docs ready, 6 weeks if not.
5. Tax implications? Significant. You need a Colombian accountant. Don't DIY this.

Specific case questions, post them — I'll answer in general terms.