The Air Water Ice web site sells Reverse Osmosis/Deionized water systems (RODI). It is not cheap, and as you are 14, you might not have the money to get a system, because they are a few hundred dollars. But you might want to remind your parents that the holidays are coming, and also remind them how much easier it will be to just make your own RODI water instead of having to take you to the stores to get some. BTW you can also get RODI water at the local supermarket. At 24 to 40 cents per gallon, it mounts up.
Bruce