Identify each and every element of a contract in the scenario provided below and advise if there is a valid contract

Scenario: Lulu, the owner of ABC Paint Sales, agreed to pay $550 for Helen Keller Sign Company to etch a custom designed sign and logo onto the front glass door of her business so long as it was done before the grand opening of Lulu's business. Helen Keller signs got the door etching finished on the morning of the grand opening.