Buying a throttle body for my 1998 Honda Civic DX?

I need to buy a throttle body for my 1998 Honda Civic DX. My mechanic said it would be cheaper if I bought the part and they installed it for me.

My question is: what should I be looking for online to find a reliable place to buy one? And does it matter if my car is a automatic or standard transmission? It's a standard shift, by the way.

Rock Auto. Makes no difference if you are shiftless or shift it. Are you sure it will be cheaper? Because lots of mechanics jump up the labor rate if you buy the part.