Best price available at the time for a genuine Canon NB-8L from a Canon Authorized Dealer.
would this battery work on a Cannon T3i digital camera?
Without checking other specs, the Canon LP-E8 battery has different contacts than the NB-8L, so it definitely won't fit the T3i What you want is available from Adorama:
Is this the genuine Canon battery?
It appears to be, I hope so, that's why I purchased it.