Between my 2 bikes I have various electronics that require 6 batteries, either 2025 or 2032. I have other stuff that take them too. I've totally migrated to rechargeables for AA's and AAA's but that's not an option for the bike batteries.
I've found that I can either buy them singly at the drugstore (or whatever) for $3-$5 or buy name brand strips of 10 off ebay for $5.
Just a tip.