Convincing the rents for an iPad...?

Ok, I'm trying to save half of my money to buy an iPad with just wifi only too, and my parents said they would "think" about it. which means no. but im saving anyways! just save your money and ask for allowance, you know, help around the house! thts the best you can do. and after youve saved the money, just go all out and say, can i have the iPad NOW? i mean, seriously, show them the money! It will take me only now till my bday May 19, and ill have $250, from bday money, chores, and allowance all together. hope i helped somewhat!