I have been walking for exercise,one hour about four miles per day I have been wearing regular Nike running shoes but I am getting bad blisters on the balls of my feet.I need a better shoe.

Sounds more like a fitment issue.  Go to a good backpacking store and have your feet measured.  Good shoes with good socks shouldn't make hot spots, especially on the ball of the foot.

Merrill makes a good shoe.  Don't believe their lies that they are waterproof, and buy the lightest pair you can get.  

I've had the best luck in walking with hiking boots.  And the best I've ever had were a super cheap pair of Hi-Tec boots.  They have outlasted anything else I've owned.  

Shoes are expensive, but good shoes make a difference when you have lousy feet like me.

Fit issue or bad socks. Pick up some dual-lined socks like Wright socks. They have dual layers so they will not give you blisters or hot spots.

What those guys said. ^^

Socks can make a big difference. I use Darn Tough Socks or if it's going to be wet DryMax. Also have some Smartwool socks but they seem to wear out faster.
I run more than walk, if I'm going to get blisters it will be on the toes so I use paper tape over problem areas.