21 Dollar Vegan Challenge

Some of you I know have heard about Vegan Hope’s 21 dollars per week challenge. The rules basically are to live for a week on just 21 dollars. Using your own spices? Subtract 3 dollars. Using your own oil? Subtract another 3 dollars. This leaves most of us with $15 to eat for the week. Another rule is that you cannot use kitchen gadgets/appliances that cost more than $15 besides your oven and microwave. I do not know how much a  blender costs, but I am sure that you can get a used/older one out there for really cheap, so I will continue using our blender.
I plan on completing this challenge during the week, and I will post everything I eat, breaking it down so you know just where each penny went. It will be fun!
I made up a rough meal plan and already went grocery shopping and this is what I purchased:

• Bag of collard greens : $2.28 (Mom bought this before we went shopping)
• A bunch of spinach: $0.89
• 6 Bananas: $1.19
• A loaf of wheat bread: $0.89
• A head of cauliflower: $2.35
• A Couple Roma tomatoes: $0.50
• Blueberries: $1.75 (This is an estimate, mom bought them previously and froze them)
• Soymilk: $2.79
• Block of Tofu: $1.25
• A huge onion: $1.16
• Celery: $0.93
• A sweet potato: $2.16
• Quinoa: $1.25
• Lemon Juice: Including in Spice/Oil Discount because it was last longer than this one week
• Better than Bouillon: Including in Spice/Oil discount
• 2 Cans of Pinto Beans: 1.38
• Box of Pasta: $1.05
• Can of Corn: $0.59
• 2 Avocados: $1.56
• 10 Tortillas: $1.99
• Apple Juice: $1.99

If you do the math, this comes out to more than 15 dollars. It comes out to a grand total of:
$27.95
However, there are a few things to take into account.
1. I will not eat all of this food by myself. I will not use all the celery, bananas, blueberries, tortillas, apple juice, avocados, etc. I live with my mother and sister, so some of the food will go to them.
2. I think I underestimated the leftovers I should have, so there is a good chance some of this food will roll over to next week.
That being said, that is what I spend on groceries,
I will further break down the cost of each meal to figure out how much money I am ACTUALLY eating.
I may go over the limit in the end, but this is still a valuable learning experience and  should be fun! :D
Do you think you could live on $21 a week? I definitely think it is possible. What strategy would you use to make your money stretch across 21 meals (plus snacks)?