Dick's has 25% off most everything online and it's automatically applied to the order. Discount can be viewed at checkout.
The Powerblock EXP Stage 1 5-50lb. Dumbbells (pair) are $224.99 with free shipping here [dickssportinggoods.com]
Each of the weight increments, Stage 2 and Stage 3 are also discounted, coming to $97.53 each with free shipping. Can grab them and the base pair for $419.98 before tax! Everything else seems to work too, such as the bench, weight stands, kettle bell, and other accessories. Since most people are interested in the weights, I only put links to the essentials, but the others can easily be found by searching "powerblock."
Stage 2 50-70lb. expansion here [dickssportinggoods.com]
Stage 3 70-90lb. expansion here [dickssportinggoods.com]
Amazon now has the Powerblock EXP Stage 5-50lb. set for $224.99 after $75 discount applied at checkout here [amazon.com]
, though there doesn't seem to be a discount on the expansions yet.