Doubt anywhere local will carry Ti, and any fastener supply will carry in boxes of 100. Online would be your best bet, here is a pair (2) from Chain Reaction
Nukeproof M6 Ti Bolt | Buy Online | ChainReactionCycles.com
These bolts don't need to be super tight so Ti would probably be okay, but Ti is only .6 the weight of steel so you're basically saving the weight of 1 bolt for $20+...
Stainless in a high Grade on the other hand can probably be found at your local Ace or OSH, Home Deposit and Lowes carry crap for these sort of bolts...
By the way they are M6 x 35mm which may be hard to find and you'll have to pick up M6x40