AAA has a car repair estimator that I'd think would be useful. Except around town, those prices are lower than the estimates one will actually get!
Autozone has a Duralast sway bar for $43/ea, and KYB rear shocks for $83/ea.
A place called Bernardi Parts has the OEM Honda parts (Odyssey). The sway bars for $31/ea (although the flange nuts are probably needed too), and the OEM rear shock assembly is $169/ea.