To add to the extensive list at http://whatever.scalzi.com/2005/09/03/being-poor/:

Being poor is knowing how to make tortillas with no fat, just flour and water.

Being poor is knowing exactly how protein deficiency affects you and how long you have before you can’t walk because of the shaking.

Being poor is counting your money down to the penny and hoping it adds up differently next time.

Being poor is a lot of walking. Walking to the store, to the library, to the places you pay your bills.

Being poor is still being overweight when you eat one meal a day.

Being poor is dreaming of a day when you can get your digestive disorder treated.

Being poor is knowing that a single person can only save enough in a year of work to survive being out of work for three months.

Being poor is never being hired long-term and never being able to collect unemployment because your jobs don’t last long enough to qualify you.

Being poor is calling ten temp agencies a day and getting them to give you one day of work a month.

Being poor is losing your $400 a month room, staying in the shelter’s emergency beds for two weeks before moving in with relatives because they begged you to let them help you, then learning you can’t pay for your cell phone anymore when you’re told you’ll never be able to donate plasma again because your address changed too many times.

Being poor is dropping out of your online vocational school because the instructors don’t have time for you if you’re not on-campus.

Being poor is being suspicious of everyone and knowing that people pity you the most when they can’t use you.

Being poor is making sure you’re exceptional at your work. If you weren’t, they wouldn’t tolerate all the time you have to take off to get treated for bug bites.

Being poor is no one taking your side in a dispute. You hold no authority, even your middle-class family believes strangers over you because you’re no good.

Being poor is hoping the bus driver isn’t counting the clinking of your change in the box so you can get away with being fifty cents short.

Being poor is wondering how people pay for their car. You couldn’t even afford the insurance on it.

Being poor is paying $50 a month for 1.5mps Internet because you can’t afford the $200 deposit for $18 a month Internet.

Being poor is needing the Internet to find a job because you can’t apply to as many places by walking.

Being poor is spending eight hours a day looking for work and knowing it will still take about six months before you find it.

Being poor is never being able to negotiate change of location costs into your pay.

Being poor is getting the first job in six years that you can get insurance with and never using it because you’d have to take off work.

Being poor is having to call an ambulance when you need the hospital for any reason because you don’t have cash for a taxi.

Being poor is wishing the hospital would give you the medicine and bill you for it because then you might be able to get the cost waived.

Being poor is not being on your parents’ insurance anymore and knowing you’re still a burden because your defaulted payments are being charged to anyone who manages to afford insurance.

Being poor is knowing the meaning of “charged off”. Your bank penalized you for inactivity when you were unemployed and not making deposits.

Being poor is watching an eviction fine grow even though the attorney garnishes 25% of your pay.