Sundays are food prep days for me. I pack up salads and other items I buy in bulk to make sure I don't waste my money.
Shop at stores that will give you a discount for buying in bulk. That's number one.
Invest in some storage for that food so it doesn't go to waste. That's number two.
I prefer Lock and Lock containers, Ball glass jars, Temptations brand stoneware and Pyrex glass containers. I will purchase some green bags soon and see how those work. I'll let you know if I see a difference. (Side eye....they cost $19 for a set sooo don't expect to see them any time soon...)
I prep everything in advance and that helps me to stay on my healthy eating plan and also save money. Nothing worse than throwing away good food you pay good money for!