There are other means than saying a "NO' to a child without hurting their feelings.

Just make a negative response even without saying "NO".

A simple statement or explanation can lead the child to be more understanding especially when it comes on money matters.

Example: 
Son: "Mom, can we buy school shoes since it's the start of school year?"
Mom: "Let's check first your old shoes if this can be used for another year.  If the shoes can still be used, we can have it spared, will buy new ones if the shoes are worn out or cannot be used. Mom is still saving money for your new shoes"