I'm going to explain why we all think that eating healthy is perceived as expensive. If you're still buying bad food and then you additionally buy healthy food, then of course your bill at the register is going to be higher. If you buy bad foods today, then next week you go and buy healthy foods then your mind sees it as an additional expense. The fact of the matter is that if you don't do a FULL SWAP of your grocery list, you will never see how eating healthy can be cheap. Not to mention the long term fact that eating healthy reduces your health care costs of your life span, so that in and of itself is a major savings.
Also, it is totally counter productive to have healthy food at home and still pick up fast food on the way home because you're tired or it's late and you're "starving" (compensation eating is a farce). Once again that will make you feel like the money you spent on healthy food seems "extra". Yes, healthy foods come in smaller packages and may expire quicker BUT if your still eating in the large portions that you were eating the bad foods in then of course its going to seem like a waste. Invest a few dollars in a serving cup at the dollar store to use to share your food and/or a food scale and this will train you how to expect what ur serving size will look like. If you don't want to do that, then actively split your meal in 2 AFTER you share it out and have the other half three hours later or for a mid morning or lunch the next day.
As I remind my weight loss team every Sunday, if you take a few minutes with pen and paper and plan your meals for the week and throw in a little initiative to pre-cut your veggies and greens (or even buy them pre-cut), then when it comes times to actually prepare a meal, you're already halfway there and you're preparation time is cut in half. Just as you would "burn the midnight oil" on other areas of your life like packing your bags for a flight the night before or studying for an exam and picking out a dress or a shirt a week before a party, the same element of preparation applies here.
Next up is your "stick-to-it-iveness". Flip flopping your buying habits between good buying and bad buying, how can you see the savings or even see that you may even spend the same amount that you are now. Also you will need to re-evaluate your eating out and cheat day expenses. We all have social lives and friends who drag us out on short notice but at the end of the day, none of them put a gun to your head and told you what to order off the menu of gagged you preventing you from asking the server to make healthy swaps on a particular meal that you like.
In concluding, making a full swap, portion control and managing your social eating will prove to be glorious when you see that eating healthy isn't expensive at all. SEE FOOD AS NUTRITION, NOT PLEASURE or a pallet pleasing expose'. You all know the line, "eat to live, don't live to eat."