Question
I have had 2 barrel cactus for 3 yrs.  Neither one has grown or produced flowers.  They are exactly the same as when I purchased them.

Answer
Hello, Marilyn - cactus are a slow-growing plant, so cactus take patience, but three years a a bit much.  Ideal growing conditions are when temperatures are over 80 degrees, and the plant is given limited water.  Sometimes folks can "love" their plants to death.

Here is a good link for cactus care:
http://www.alexandgregory.com/cactus_expert.html

These may yet surprise you - they are still alive, so hope "springs eternal" ~Marc