I look first for the lowest price on ebay, so long as it is from a first rate seller. That usually means, poor_fish, belote or supremesolution. Poor_fish must work on very slim margins at high volume, because their prices are almost always the lowest.
Yourcornerstore has good prices and service, but their inventory is often zero. At least thats my experience.
Newgraham has excellent service, but their prices are higher than ebay. Often by a good margin. But I have dropped a ton of cash there over the years, and they usually throw your order on the UPS truck about 10 seconds after you complete the transaction.