For a new one you should expect around $50 if I'm not mistaken. That's for the oem replacement. Dealership will have them of course, or can get one. Ebay may have used, fixed ones, as well as new. Otherwise I know both www.hondaautomotiveparts.com
and http://www.partsgeek.com(A+ shipping) carry them.

Otherwise you could just re-flow or, preferably, replace the solder on the old one. Normally it's just the solder joints that are bad.
I re-flowed mine, same exact relay. Not hard but take your time and best to wait just a bit after you've flowed one joint if you need to go at it again. If you get it too hot it can burst, spraying a small amount of solder in your face.

Good idea to wear glasses.