The teenage years weren't more expensive for me,
I have two DDs, now aged 23 and 21, and I have been a single parent for the past 12 years, for most of that time I have been on disability benefits, there just wasn't the money for anything that wasn't essential. Luckily, my girls have never been demanding, and never asked for a thing, they didn't have laptops or hair straighteners, and have never been into computer games, so no XBoxes, or anything like that.
I did buy DD1 a cheap mobile when she was 12, but that was out of necessity, as my XH would not allow the girls to even say goodnight to me when they were away at his on visits (he lives over 300 miles away)
I'm still on disability benefits, but am trying a part time job for the first time in many years, and both DDs now have good jobs, so things are better financially for us now, but we're not well off by any means.
Growing up, the girls were not allowed to just help themselves to food, as once something was gone, there wasn't the money to replace it for another week or so, so things had to last, they never went without essentials, but there was many a time I went without eating, to make sure there was enough.