Earphones are very cheap, and because they break so easily, they are always needed. Teenagers are not cheap to buy for, as anything tech costs $$$. It depends upon their interests and what you mean buy ' low budget'. My daughter would be very happy with a gift voucher from a book shop for $20 or $30. Otherwise go to an Op Shop and get used ones for hardly anything. You can get cheap perfumes for under $10, but my daughter would prefer the Kim Kardashian ones. You could get a gift voucher for the local cheap cinema. My boys are a bit harder to buy for as they generally want something like a game or something for the phone. Once again, with a gift voucher, you can limit the cost to how much you want to spend. If they have hobbies or sports, you might be able to get something related to that. I have some great gifts for my kids, but they may not appeal to your kids, or be available where you live. A new attraction has opened here, so I got a $25 gift voucher for that for the kids. It depends on their interests, but you do have to think outside the square.