ITA, the DSL is cheap and you can play a lot of different games on it. My nephew is 4 years old and when he was visiting 6 months ago, I let him play with my phone and he dropped it several times(thankfully causing no damage). :-( The next time he visited I was smart and charged the DSL and kept a racing game in it. And the time he visited after that my sister bought him a DSL and we played Mario Kart against each other. fun times...
Still, I at first looked for preschooler specific games in the market and was disappointed by the lack of variety.