For years, I got blisters everytime I put on a pair of sneakers. I was convinced that I was buying the wrong shoes. I tried dozens of pricey athletic shoes and had the "experts" fit me and recommend shoes, but the blisters continued (always on my heels).
Then one day, I just mentioned this problem in passing to a friend who is a pretty avid runner. He said, change your socks. He turned me on to "running" socks. They have very little or NO cotton in them. It was a MIRACLE
I could wear athletic shoes like everyone else. NO MORE BLISTERS!
They're much more readily available now than 5 or 6 years ago. You can even find some in Wal-Mart now. Look for socks with nylon, rubber and lycra. And don't get socks that are too thick. The lightweight ones will protect your feet and keep them from getting too hot.