It's going to be expensive no matter where you go.
Mouser -- 100 pins = $16.40, 100 sockets = $17.30
Digikey -- 100 pins = $18.79, 100 sockets = $18.24
Jameco -- nothing comparable to these.
Great Plains -- 100 pins = $12.50, 100 sockets = $12.50
For plastic body housing - the Great Plains pricing for is typically less than Mouser.
$25 worth of housings?