Can you talk about what you were spending and eating before, and the healthy things you're buying now? In my experience, staples like chicken breasts, rice, potatoes, carrots, skim milk, etc. should be quite affordable.
I'll echo the poster above. Would you mind telling us what were you eating then, and what are you eating now? I can't imagine tap water and veggies + some protein being more expensive than fast food with coke.
Some of the stuff I bought before was literally cheap trash. You know you can get personal pizzas for $1-1.50, a full box of jalepeno poppers or cheese sticks for $1 a box? 10lb bag of rice (which isn't the best for weight loss btw) for ~$5 of which I could easily eat 1lb per meal mixed with mayo, dressings, etc which are cheap as shit once you spread them out. Get a whole pie for $4 or less depending. Sometimes even treat myself to a $5 Little Ceasar's pizza. Cheap as hell stuff like that, but all of it terrible. Also maybe going tmi but I had to rely on food banks some months to get by; and let me tell you, the one I went to would limit the amount of 'fresh' fruit/veggies you could get and limit you to about 2 cans worth of other food. But I could walk out with 2 whole sheet cakes, trash bags filled with rolls and bread. You know the real healthy stuff, for free.
The biggest change for me was having a low paying part-time job and then changing to a full time higher paying job. I was actually able to buy the food I knew I should be eating but couldn't afford before. Now I buy whole wheat multi-grain bread, sliced deli turkey and cheese, eggs, milk, grilled chicken tenders, healthy snacks ~200cal, healthy choice frozen meals when I'm in a hurry which come in ~200-250cal, spinach, tomatoes, onions to add to meals. The leanest hamburger meat when I go for something like that instead of ground chuck which has more fat content.
All this stuff adds up and costs me more than how I was eating. But even taking out the food I got for free, I could bring a meal in around $1-2, when now my meals are closer to $3-4.
You don't have to buy fast food, expensive pizzas, chips, soda every meal to be eating unhealthy. Trust me they make it easy to eat that way on the cheap if you know how to shop for it. Hell sometimes I'd just go to the dollar store, spend $15 and have meals for days. None of it in any way healthy of course, but there you go.
Edit: Almost forgot stores sell 48 poptarts for $8-10 depending on the type you get. lulz. You know the serving size is 1 poptart yet they come in packages of two? xD The healthiest of cheap desserts. /s
Edit2: Again keep remembering things I used to buy. I see people complaining about juice in this thread so just wanted to mention Walmart sells their own apple juice like $1.50 or less I think for a whole jug of it. Again, cheap but bad for you if you overdo it. I'm sure you could find even cheaper juice if you looked.