What are some good financial tips for a young enlisted US Army soldier?

Unless you just need to get out of the barracks, don't. Stay in there. It's free all the way around.
Eat at the chow hall. The expense of buying food or eating out adds up quickly and why waste the $100 bucks a week.
Invest in yourself. Education.
Maximize your TSP contributions, it really adds up over time.
If you find you need a car, look to the post/bases "lemon lot" as these are vehicles that are being sold by members that have PCSed and could not take it with them. If you need to buy a car, DO NOT buy local around your duty station as they are higher in price and interest rate. Do NOT mention that you are in the military as that just brings out the vultures.
Avoid that first credit card for as long as possible. DO NOT get the STAR card that exchanges offer you get better rates in banks and credits unions and if you get in a pinch, they are more lenient than STAR. Use cash to pay for what you want. If you cannot pay for it all at once, save it up then get it.

Lots of good advice here from about everyone. But I'd add that if you are married or become married, marry a woman with a job and good work ethic who can help with expenses and don't start a family until you make at least E-4.

Deal in cash. You do not need a credit card until you know how to manage you money. There are money management courses that are offered, go, learn and apply it. Stay out of dives. Just deal with needs not wants, if you don't know the difference talk to your first sergeant, they will instruct you on the difference.

1. Stay as far away from credit cards as possible. They are an anchor that nearly impossible to unshackle and it's a constant drain!
2. Use the education benefit that the military provides. You won't always be in uniform and it opens tons of doors, many of which will provide with promotion opportunities and higher salaries!
3. Save money. TSP, IRA, Savings account. You will need some that is easily accessible (this will keep you from the desire to use a credit card wastefully), but you need some that you can't put your hands on if you have a tendency to binge.
4. Although we have all complained about the Chow Hall (DFAC), it is a huge money saver.
5. MWR has a lot of money saving recreational offers.
YOU'RE WAY AHEAD OF THE GAME BY ASKING THESE QUESTIONS NOW. Best of Luck!!!

Don’t get married and start mKing babies while you are still an E1

Open a bank account that requires TWO signatures for check or withdrawals an a pre-paid debit/credit card with a fixed limit.

Direct deposit & learn to live with the self-imposed limits.

Act like an adult.

Avoid the pretty girls at the local malls trying to sell you electronics (at 20%+ interest!).

If your bills are $1200 a month, you should save a 6 month surplus or $7200 in case of emergencies, government shutdowns, etc.

_Your budget for necessities and "fun" is ___% less than your take home. I suggest 15%.

_Until you are debt free, that __% (over and above minimum payments) goes to debt reduction. Kill the highest interest rate debt first.

_ Once you are debt free, that __% goes to immediately available savings. That savings is only to be touched for emergencies, until you have three months take home pay saved up.

_Next, set up an investment portfolio. Set up an allotment so that 2/3rds of that __% goes to your retirement. 1/3rd goes to "Savings for big things I want in the future."

_Never finance a luxury/nice to have item. If you don't have the cash, you haven't earned it.

_Don't turn up you nose at buying used stuff. You can furnish a starter home from garage sales, thrift stores, and craigslist for 20% of what it would cost you new from a retail store.

Buy a vehicle of Craigslist that’s under 4K, set up a Roth 401 or 457 and contribute at least 7%. Create a savings account and put in $100 each pay period. So $200 a month. Don’t get Married at least after your first deployment or when up for reenlistment. Credit cards are a no-go.