IF THEN Formula with Range Check

I'm looking for an If Then Formula that checks for numbers in a certain range and spits out the correspoding number. Thanks in Advance.

If John sells 6 units, then $20/unit.
If John sells 12 units, then $40/unit and so on.

Here are the ranges:

0-6 $20.00
7-10 $30.00
11-15 $40.00
16+ $50.00

depends on how range is specified! do you mean total is in one cell say b1=6
or say b1=1 c1=2 d1=3 total =6

oh good another duplicate post ,i just love thinking about it then having it answered elsewhere NOT!
http://www.excelforum.com/excel-gene...ula-range.html