How long after the cast comes off a broken foot till able to walk again?

Soon: When cast taken off this means the fracture healed, then you should be to walk with some limp, 2 weeks should be fine to start walking again.

Depends: This would depend on what was broken, how bad it was broken, was surgery done to fix it. But if out of a cast you should be starting to progress to some weight bearing and as comfortable be able to progress to full weight bearing.

May vary: Healing rates may vary on various factors. In general bone may take 4-6 weeks to heal. For fifth metatarsal base fracture the healing may be delayed due to a limited blood supply in that area. You may be placed in a cast initially and then be asked to wear a rigid walking boot for the remainder of the healing process.