You're 100% right, the genesis of this thread was an argument I got into about repeating past mistakes. Paycheck to paycheck is a bit of an exaggeration, but it has been hard when unplanned situations come up... for example our car was towed for being too close to a walkway and the stupid excessive $900 tow charge made my heart sink and put me in panic mode- I was hoping that panic mode over money was behind me...  I'm guilty too,  and it's always the little things with the mrs.  Like she'd walk into a cvs for one thing and end up spending $40, which quickly adds up.  I'm (was) the gadget spender, she was the little purchases add up queen.  It's a lack of consciousness about spending that needs immediate action for sure.  I'm going on a $30 a week allowance for each of us then working on a firm budget this weekend.
		
		
	 
First: PAY OFF THOSE BS DEBTS! There is no reason to carry cc debt. It's cancer. ditto your car. Pay it off pronto. Excess per month. Just get rid of it now. 
You are losing insane amounts of money holding that kind of cc debt. It's bonkers. 
Rather than simply give yourself $30 per week allowance, start tracking your expenses, now, and set monthly goals/limits. Track every single dollar spent between you and missus, and keep them in monthly categories: groceries/food, booze/entertainment, bills, mortgage, "want stuff,"
You can't do much until you know ho much you are spending in each category, every month. Bills and mortgage--there isn't much you can do there outside of trimming your cable service down, shopping around for better insurance rates or cellular service, being more responsible with water, electricity, gas, etc--but you will soon hit a hard minimum that you won't be able to beat. Behavior here is pretty easy to change and maintain: Hey, I can actually live at ~78-80 F internal temp during the summer, or 65 during the winter...things like that. The savings, if you can stay comfortable, will astound you. ...but only do it if it's worth it.
I find the biggest savings come from food: shop better and more efficient, cook and, if you don't know how--LEARN. Stop eating out for lunches, every single day, and reduce needless spending in restaurants. Still, have fun from time to time, go and dates with the missues and whatever, but you might be able to shave at least $200 per month between the two of you, likely more, depending on current habits.
For "Stuff spending," 
make that your monthly allowance. Do you really need a brand new monitor now? No, you really don't. Can you swap a few month's purchases now for a new monitor several months later? why not? Don't make quick purchases as soon as you decide you want something. Give it a day or two before clicking the buy button.
You'll start finding money where it didn't exist before, you will first be angry at yourself for throwing that away all this time--which is good, but don't dwell on it--and then you will realize all of that extra cash is now your savings/investment money.
This is when you start dumping into low fee Index funds as everyone else has suggested. Ignore the market, just keep buying shares every month with your monthly surplus. Build your emergency cash as well. It's amazing how confident and comfortable you feel when you effectively gain control over bad habits like that and happily watch your money grow, steadily and surely. Ignore the dips and just buy more shares with the same money.
If you haven't yet checked out Mr Money Mustache over this last week, I advise you to do so. He can seem nuts and his philosophy feels very cultish, but if you can embrace at least some of his good habits and make that philosophy fit your lifestyle, then all the better. It's a good kick in the ass to get yourself going.