Lots of interesting advice at the Reddit link above.

Good Reddit comment:

1) Sell everything you don't need : TV, XBOX, Mac Desktop (just keep the laptop), etc. 

2) Use Google Fi as your mobile provider when your dad cancels it. It is cheap and cost efficient. https://fi.google.com/about/?u=0 (I don't know if you still need an invitation, but if you do then DM me and I'll invite you.) 

3) Go to school and work part time. Don't waste your life away on a minimum wage job without trying to improve yourself. Find a community college or JuCo and figure out a path and career you want. Working part-time will help subsidies some costs, hopefully you don't need to take out a loan, but if you do, you are betting on yourself. Don't forget that. That loan is you telling yourself you believe that you will use this education to better your life as well as. E able to pay this loan back. 

4) Find all of your local food banks and capitalize onto them. You won't have to waste money on groceries. Buy a nice cookbook that has simple 30 minute recipes and LEARN TO COOK. Let me repeat this one more time LEARN HOW TO COOK. IT WILL SAVE YOU SO MUCH MONEY. Also, do NOT BE SHY about going to these places. I've worked at foodbank and we understand and do not judge anyone. We welcome you and try our best to help individuals. 

5) DO NOT eat fast food. This wastes money!

6) You are twenty and do not need to worry about health insurance due to Obama Care. Go to the Obama Care Website and call them. You have to sign up for this. Do NOT forget this. 

7) Find out if there are non-profit organizations that help individuals in your age group. Usually there are numerous organizations that can help you along the way.

TLDR: Self stuff you can live without. Go to Foodbanks. Google Fi. Register for school while working. Obama Care registration. LEARN HOW TO COOK. NO FAST FOOD. Save money. Call non-profits for housing and general help.

Try to make that part-time job someplace offering truly beneficial employee discounts, like department stores for discounts on business clothes.

Good idea, Marlene!

Fast food doesn't have to be entirely bad; same for regular restaurants. Order "to go", then use the food as a base for soups, stews. Chinese (wor wonton soup) and Mexican food is especially good for this. Add water, veggies, noodles or rice — can last for several meals and get the flavors without having to buy lots of seasonings. 

In general though fast food and restaurant food is more expensive and less nutritious than what you can buy in a grocery store. 

More on "learn to cook" as a money saving strategy:

http://pandawhale.com/post/72230/if-you-want-to-save-money-learn-how-to-cook-and-drink-more-water

Another good Reddit comment:

• You need somewhere to park long-term. I'm assuming you don't have friends or family willing to let you stay with them, but if you have any at all, even distant ones, who'd be willing to give you driveway space for a couple of weeks you can at least not worry about gas money. If not, I'd go to a homeless shelter for advice or even ask a police officer if they know a place you can park without getting ticketed. 

• Your number one priority should be food. You need to be in problem-solving mode so you want hearty, healthy meals. Check out /r/EatCheapAndHealthy but a good start would be to divide your remaining cash by the day until your next paycheck. $80 works out at about $3.80 a day for food for the next 3 weeks. 

• Find a place where you can use the wifi for free in case your phone contract is cancelled. Then you can always reach out to friends or family, search for nearby homeless shelters or charities and check out these subreddits too: /r/Homeless /r/AlmostHomeless /r/Vandwellers /r/assistance