i'm fortunate enough to be fairly young (only 21 :P) and being rather well off.
after all my bills are paid, groceries are bought, gas is purchased, etc. i still have about $1900 to put in the bank, or spend on any of the non essential stuff. i consider myself to be living rather well below my means.
i was fortunate enough to be raised by parents who had experienced some rather tight financial situations. so its been beat into me since birth, that "money doesn't grow on trees"
if theres one thing i've learned from my father.. its the value of being able to do for yourself. he's a journeyman electrician by trade, an exceptional mechanic by hobby, and a worth while plumber, carpenter, and roofer. pretty much anything that needs to be done in construction, or on a farm, he can do. i can't recall how many times we've had to fix a car, repair a busted pipe, or add a lightswitch/socket.
i highly recommend that everybody learn at least one secondary skill, that you can rely on if something needs done. trust me, being able to spend $50 in materials and a few hours of your time, is far better than spending several hundred to have somebody else do it for you.
from my mother, i learned what you should spend a few extra bucks on, and what you can get away with getting cheap.
whenever possible visit a farmer's market. 9times out of 10 you can get your produce far cheaper there than you can at a supermarket, and its undoubtably fresher and better for you.
medicines, and breakfast cereals, go with the cheap stuff. most of the time its made by the same manufacturer anyhow.
buy in bulk and freeze what you don't immediately use. not having to run to the store every night saves you money on gas. and you get more for less anyhow.
some extremely perishable items, like milk and bread, only buy as much as you will use. if you buy a gallon of milk, and only use half before it goes bad, your wasting money. i buy these items as i go, the price is pretty stable on these items.
don't buy soda's, bottled juices, stuff like that.. get the frozen concentrate stuff, it keeps longer and costs less.
remember, pride doesn't pay the bills! if you honestly find yourself barely squeeking by, and your not spending wildly, look at government aid programs. if you need the help, ask for it, theres nothing welfare if you genuinly need it.
take your tax refunds for a few years and put them towards your bills. if something goes wrong you'll be thankful for that extra month's payment.
never ever pay the minimum on your credit cards, your only paying the intrest and not the premium. even a few dollars over helps.
last.. resist the urge to impulse buy
you don't NEED to be spending 50dollars on that new video game. the price will drop in a month (and give you ample time to save as well)
think of it as being on a financial diet
plan everything out ahead of time, and stick to it.