Its too late now but the manager could have been a bit more customer friendly in this issue and explained why the price difference.
You never said if the manager offered to refund your money. Had he done that then I would have taken the money and gone somewhere else.

Also it seems that this salesperson was not knowledgable in the pricing of the table set. I am sure if the manager was that gruff and rude the employee is probably no longer employed there.

Keep us posted...it will be interesting to see what happens.