Often, I will find ingredients on sale and buy many of that item. When it is an ingredient we use often, we can save money using these items over time in meals. This simple principle allows me to further reduce the cost of meals for our family. Not only did I save money by buying on sale, but chopping them myself saves quite a bit of money over buying pre-packaged bags of chopped bell peppers in the grocery store's freezer section.
It also saves me so much time in the kitchen. Instead of chopping up bell peppers every time I need one for a recipe, I can take 15 minutes and chop up many bell peppers! This saves time both in food prep but also in time it takes to clean up. I can easily pull a bag of something I previously chopped, cooked, or mixed together from the freezer to add to meals throughout the month with no added work.
To process the bell peppers, begin by removing the internal ribs and seeds. Then slice or dice the peppers into a form you can use in future recipes. Place a single meal portion into a quart sized freezer bag, pushing as much air out as possible. Then tightly seal bag closed. I then place all of the quart sized bags into a gallon sized freezer bag to keep things together in the freezer for ease of finding later.
To prep the onions, I did the same technique as the bell peppers. Dice or chop the onions to the size you prefer for meals. Then portion out the standard amount you usually use for one meal, I always use one onion's worth. Store in freezer bags for later use.