How lucky are you normally?

You might be able to ride for a considerable length of time on one broken spoke or you may start breaking spokes left and right. I'm thinking that depending on a bike with a broken spoke for daily transportation for a whole month is a risk that I wouldn't take. Broken bikes never get better by themselves. They might get worse if they're not properly repaired.

Whether your local bike shop has the right replacement spoke in stock depends on exactly what kind of wheel it is. There are so many different wheels today with out-of-the-ordinary spokes that shops typically don't carry replacements for everything. Again, you might be lucky, maybe not.

If you were to bring your wheel for me to fix I would replace the broken spoke and check the ension of every single spoke on the wheel. I think that's the right way to do it. That's going to involve about 1/2 hour's work so I'd want $30.00 for the job. Doing anything less (replace the broken spoke and retrue the wheel) would be to return the wheel to the condition it was in prviously. What it was previously was a wheel that's about to break a spoke.