I want to insert a total in column C for names in column A that have the
first several characters matching (I was thinking of using the LEFT
function), but I only want the total to appear when the aggregate amount for
a name is more than 100.

Can anyone help me?

A B C
Contributor Name Amount Over 100?
ABBOTT DOROTHY C 25
ABBOTT DOROTHY C 15
ABBOTT KATE 100
ABBOTT KATE J 50
ABDO MICHAEL 25
ABE KUMI 1400
ABELES KATHLEEN K 100
ABELL NANCY 10
ABELLERA EDDIE 25
ABELLERA ELLEN 25
ABELLERA ELLEN M 100
ABELLERA ELLEN M 200
ABELLERA ELLEN M 50