High heel tips needed!

Mea
Hello ladies! So I recently got a job in which I have to dress in business attire, leading me to wearing high heels. In the past I rarely wore heels/I only have 2 pairs of cheap $20 ones! It's my 2nd day& my heels are already blistered from rubbing on the back of the high heels& my toes are killing me! Anyone have tips on how to avoid blisters and hurt toes? 
Also what brand would you recommend for a nice comfortable high heel? I'm able to spend about $100 on a pair. Thanks ladies!