It probably depends on the teenager, but my niece has been raised to be frugal. She's had a teen checking account for a while, but the debit card attached to that account did have a $40 limit that was imposed by her mom. I don't get the impression that she'll immediately go wild with a credit card. I had a Discover Card when I was 18 or 19 and always paid it off in full, which was a habit my parents taught me. All of my purchases weren't incredibly logical at the time, but I didn't go into any debt or pay interest. (Overdraft fees on a checking account could be even worse than paying a small amount of interest - if she gets to that point.)
My main concern with using a debit card is the lack of protection. Chase has always provided me with extremely vigilant fraud monitoring. Suspicious transactions aren't approved and I'll receive a phone call, text and/or email within seconds of an attempt to use my card on something questionable. I haven't seen the same kind of attention to detail from banks and normally while a transaction is being disputed, that money won't be in the account for at least a few days.
I feel like I can lead by example when it comes to financial education. I try to be pretty transparent with all my data - she's seen my Mint account, my retirement plan, and my income is public record since I'm a government employee. My wife and I talk about spending, income, paying bills and the pitfalls of ongoing expenses in front of her often.
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Here's what I'm thinking my retirement account advice for her will be today:
1) Maintain $1k in the checking account (for paying for classes, books, gas, Cheetos, etc. [it's a community college])
2) Once you have $2k, put $1K in a Roth IRA with Vanguard
3) Contribute a minimum of 10% of any income(paychecks/fin aid) to that Roth IRA (ideally a higher %, but 10 is a good start)