I do my own finances (heck, I do my own taxes as well); I'm not the best with it, but I manage. Though perhaps the situation here is different compared to across the pond.
My income is more steady than most people who are actually employed, even though it's significantly less, but alas, that's what one gets with collecting welfare.
I manage my finances through some software, yet I in general know how much money I have left and that seems to work fine for necessities. There's some money left for "fun" and I might even save up a bit if the situation allows for it.
I'm also one of those who regularly buys groceries on sale. The store is about 10 minutes from my place, so it's not much of a hassle to run there just before closing time and find they have all these 35% to 50% off items that are close to expiration date.
Luckily here it's not that odd with added taxes. Taxes are already on the pricetags here (at least; I once hear in the US taxes are often added at the register, rather than printed on the pricetags; I might be wrong). Though added taxes in general here are either 6% (food) of 21% (non-food), which makes some things a bit silly even if they're basic neccesities.
I will say that I have come a long way from horrible moneymanagement. I was horrible with money in the past and would often end up in debt way before any new income was in and had to skip a meal here or there because I had to manage the bit of money I had for the next 7 days (and at such moments I rather eat out of neccesity than habit). I remember ending up with €5 for the entire week at times, and that was when I already was heavily in the negative on my account.
I wonder if it's that I became more responsible or if it's just that my life seems more "complete" and that I've found more things that are cheaper (or even free) to do and enjoy. I think the latter though.
Yet I'm obviously not there yet, but thus far I'm managing fine and keeping an eye out on my balance regularly without trying to worry over it too much.
But the money in gas is trumped by the total savings in food each month. Still, whenever I contemplate buying things I factor in the cost of gas in getting there.
This is a concept neither of my parents grasp for some reason. They drive everywhere and often drive great lengths for a discount, yet the gasoline expenses for some reason never occur to them. But I suppose; a similar situation is the one where I pay, say €3 for my trainfare (and the station is down the street), and my parents visit the mall and have to spend money on gas and a heavy parking fee...
I know that if I had a car, I would micromanage gasoline to absurd lengths, which is why it might be good that I don't own a car. I'd probably end up with tables and charts to map out the optimal and cheapest routes... as well as going full on rage if there's a detour because of road maintenance... nope, that's the type of things I should not get myself into, lol