I reserve opinion about stfu for stfu.

But let's break your situation down with some questions.

I walk or ride my bike anywhere I need to go

Do you walk or bike on the freeway, or rather do you happen to live in an area with accessible walking and biking lanes? My area does not.

My non-tuition expenditures total under $700 a month including food and rent. For two of my three years in college, I did not have a job.

I checked, non-tuition rates at all of the schools in my state cost ~$800/mo for dorms. The dorms appear to be single occupancy with no affordance for a married couple, they do not allow year round occupancy, that means we'd be out $1600 a month for worse living conditions and still have to figure out what to do during summer break.

That being said, we did have an opportunity to rent a room in somebody's house and saved $100 a month (sublet rooms in my area run between $600-700/mo), the tradeoff was around 2 more hours a day in transport time by car + fuel costs. Doing the math and the money worked out about the same, but then we'd have to spend more time on the road instead of working or studying, and we'd have less privacy. We seriously considered the local homeless shelter, but they charge $20 a night per person, or $1200 a month for the both of us to be itinerant.

I did a breakdown somewhere else in this thread on what our costs were, it was only because of some grants and a few student loans that we could even pay for school at all.

One thing we didn't expect was that it would take two years for my wife to get her work permit. But 9/11 happened and fucked up immigration royally for a long while. It meant she couldn't work at all during that time. Once she started working things eased up quite a bit.

but you should seriously consider how many of your expenses were/are necessary.

So what was unnecessary?

At the time we had no car payments to make (the vehicles were owned outright), food was the cheapest garbage we could find in the "discontinued" bin at the dollar store (literally), clothes were what we started with (I didn't purchase a single article of clothing for 2 years), our #1 expense was housing, which short of couch hoping for years on end there simply wasn't anything we could do about. We had no furniture, at all. We didn't even have dishes for most of the first year! We both ate on around $5-7/day. There literally was no other expense that was possible to cut by our reckoning.

Nothing makes you think about what every...single...thing...costs than being poor. We even knew, down to the item, and sometimes to the ounce (since different packaging formats make direct comparisons hard), what we could buy for cheaper at the grocery store vs. the dollar store. We reused cooking oil in an old coffee can I took from my work when it was empty. A package of instant noodles and 20 ketchup packages made 4 servings. We used to go to our local grocery and argue with the manager when the sell-by date on canned goods got too close so we could get case of canned green beans for a dollar, then eat only green beans for a week. I can tell you that a package of one day expired hotdogs and 20 more ketchup packages can make an extravagant stir fry that lasts for four meals. Add half a chopped onion and it becomes 4 star. It's not possible to eat cheaper than that without going completely free.

We didn't have cable, a land-line or cell phones (I used AOL and other free internet CDs and a long phone wire to one of my neighbor's land-lines if I needed to get online at home, or just used the school's computer lab when it was open).

We actually sold one of our cars during the second February because there weren't enough work hours in the short month to both pay rent and buy groceries.

What where was the extravagant and unnecessary thing that we could have cut?

For two of my three years in college, I did not have a job.

And yet tuition, rent and food materialized?