"Calculate Date range" wrote:
.. setup a formula to check for a duplicate entry.
Product name Price (in $)
A 3.00
B 1.20
C 5.00
D 3.00
( I plan to put in a formula if the price is the same price
compare with the rest of the price row.
when I key in the price at $3.00
the system will prompt me or give me an error.

On the face of it .. try this

Assume table in cols A & B,
data from row2 down
price in col B

Select col B
Click Data Validation
Allow: Custom
Formula: =COUNTIF(B:B,B1)<2
Click OK

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Max
Singapore
http://savefile.com/projects/236895
xdemechanik
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