I already have Denso plugs ready to put in my engine. But I have some idle time to Google.

NGK plugs for b18c1 is PFR6G; this is from www.ngksparkplugs.com, as well as from www.drivewire.com. My manual is in my car, which is too far away right now.

So Googling on NGK PFR6G, I find sites with the following pricing (each):
$12.50 - Volvo shop in CT
$16.12 - acurapartstore
$12.64 - drivewire
$12.35 - clubplug.net
$6.15 - ebay auction

Damn! Should have bought on ebay.... or tried an auto-parts store.....:doh: