Oh, what a shame that you can't buy an iPad or a new smartphone. Answering your question, thought, I don't like gadgets very much, yet I have a cellphone. They are often bad for us, they damage our eyesight, they do often cause sleep privation via addiction to it. But on the other hand it provides us with almost everything we need: information, movies, music, calculator, etc, etc. It can entertain almost anyone for a long time. But in my opinion the only gadget I would need for now is a cellphone. I don't want to buy any gadget for now, cause cellphone while is not as modern as smartphone but it has the primary function which the phone was invented - calling everyone you need while not at home or work. I think that tablets and smartphones should be sold only at the age of eighteen because before the adulthood we should focus on studying and gadgets do disturb us which is bad. While cellphones are gadgets they only provide us with the ability we need in our modern society - an ability to call parents, police, anyone, when necessary. You may say: "But cellphones do have some sort of games too!". While that's true, they are often much more simple which results in less popularity, and overall I think that when you're studying hard, you won't have time to play.
Hope I've answered all of you questions,
Write me soon,
Jane.