I feel old, they didn’t even really have cell phones back when I paid my first bill.
Which was half of the phone bill for my freshman dorm. For some odd reason, the school made every single pair of roomates sign up with Bell Atlantic separately, schedule their own installation, and pay the account setup fees. Every year too!
Well, let’s see…when I was 14 I started buying my own clothes. It was put to me this way, “We’ll buy you this, these or those. But if you think you need designer jeans or shirts then you can buy them.” So I did.
At sixteen I saved my money for a down payment on my first car. Made the payments monthly, insurance and all. When I graduated from high school, I already had my apartment rented and had the new furniture delivered the next week. That was June 1st of 1980. It was my eighteenth birthday present to myself.
BTW I worked an average of 60 hours per week in highschool and still stayed on the honor roll and ranked 13th in my class of apprx. 300 students. There were times when as a teen I helped the folks pay “our” bills.
I was raised by an “old school” depression farmer in East Texas. I worked in the hayfields, watermelon patches, and cut cordwood in my youth. When I got an “inside” job paying good money… 
For your lady to lay on?
The first bill I ever paid was on an oil company credit card. The balance was somewhere between $10 and $20 dollars.
I mailed it but forgot to sign the check.
The bank paid it anyway.
Since this is basically a poll, I’ll move it to IMHO for you.
Cajun Man
for the SDMB
I always paid things like gas and some food and clothes on my own once I started working summer jobs, when I was 16. My first bill, though, in my name, was with sympatico - a dialup internet connection at the house I was living in in first year of university. My parent helped pay my rent, so I didn’t really consider that to be my bills. Phone, cable, heat, hydro etc came later, in another apartment where it wasnt included in the rent.
This past week, though, I just went through all the work and steps to transfer my car ownership/registration to Ontario as well as get my license and health card, and arrange new car and rent insurance (I was on my dad’s plan til now). All of this was kind of scary! Real Life consists of a LOT of paperwork and phonecalls! But it’s basically all done now, and I am quite proud of myself for having managed it all (although I did call home to my father a lot to see if prices on some things were reasonable). Add to that that I am now a ful-time, permanent chemist at work, I have a salary, not an hourly income, I have life,health, dental, insurance, a penson plan, all sorts of things! Real World Big People stuff! Crazy.
Tomorrow is my birthday, so I will drink like I was 15 and forget all this crap about " responsibility!"
Rent, for sure. After that, bail.
Had to be that split freshman year phone bill (long before cell phones). But what really made me feel like an adult in the financial world was getting my first checking account (also freshman year). I remember that my roommate’s mom took us to the bank and explained the whole process to us, and I felt like a grownup. That ATM card was so cool and high-tech – they had just been introduced.