Wow do it yourself its a matter of unscrewing the old plugs and screwing the new ones in w/ a ratchet and a sparkplug socket. The stock honda plugs are just NGK copper plugs. according to ngksparkplugs.com your car runs ZFR5F-11 (pre-gapped) and those are $2.44 a pop.
http://sparkplugs.com/results_cross....R5F-11&x=0&y=0

even with platiums they are only $2.68 a pop
http://sparkplugs.com/results_cross....FR5FGP&x=0&y=0

double platinums are $11.71 a pop
http://sparkplugs.com/results_cross....5F-11&x=57&y=9

and iridiums are $6.95 a pop
http://sparkplugs.com/results_cross....FIX-11&x=0&y=0

either way your mechanic is wack. $88 for changing sparkplugs is ridiculous even with double platinums.