1996 Mazda Protégé, 128,000 miles,
How does one know if an axel is bad, what is the cost to repair?
Thanks!
The best way is to have the vehicle put on a lift and checked by a good independent mechanic. A quick way you can check off the lift is as follows: Find a large deserted parking lot and drive in a tight circle both left then right. If you hear a nasty popping sound…the axle is bad. You will notice one side will be a lot worse than the other. Pricing is best left to your local independent mechanic although others may have a good rough estimate.
Have it replaced along with your tie rod posted elsewhere. The cost is dependent on the labor rates in our area. Smalltown, Mississippi will be cheaper than Megalopolis, Calif.
For both repairs, which should include a front end alignment, I’d guess $300- $400.
Another symptom can be a front end vibration while accelerating (say, up a hill) that stops when you let off the gas.
it starts hanging out and smoking, makes a nuisance of itself, noisy and unpredictable, finally it gets locked up and leaves you all alone in a bad neighborhood. 
Thanks for all of the suggestions! @ wesw it was good to laugh. @ missileman and @insightful, I will try these two things to see if there is a problem. @ MG McAnick, I appreciate the savings aspect of your response.
@wesw: Axel Rose went bad years ago…
Good one Wes!!!
I thought it was when the skater landed on her butt. Bad Axel
What a wheel revolves on. Axle
Yosemite