I know so many people that think they cannot eat healthy because it is too expensive. I do agree that many "healthy" foods are more expensive than a lot of the junk food around, but if you shop around you will be surprised at what you can find for decent prices.
My grocery shopping is kind of a pain because I have to go to 3 or 4 stores to get what I need. But, to me, it is worth it. I am a big fan of the Morningstar vegetarian products and an even bigger fan of about every Amy's Organic product out there - but I am not a fan of the prices at my standard grocery store. Surprisingly enough, Target carries many of both of their products along with a number of other "healthier" option foods for almost 1/2 the cost of the typical grocery store. If you have a Super Target or a Super Walmart close to you, you are even better off as many of them also have excellent produce available again for nearly 1/2 the cost. If you are lucky enough to have a Trader Joes around, their food, even their organic foods are dirt cheap. But be careful because they have lots and lots of goodies that may be organic but are not necessarily good for you!
Big discount stores like Costco and Sams can be great options for you as well. Both offer a large selection of "healthy" packaged foods as well as fresh produce, breads, organic eggs, milk, etc. The kicker there is making sure you eat it all and it doesn't go to waste. If you saved 50% but throw away most of it, you aren't really saving yourself any money. Be mindful of what you buy and what you actually eat.
Finally, it is getting to be Farmer's Market season again so get out there and find your local market. Many farmer's markets carry amazing produce as well as nuts and seeds, dried fruits, natural all fruit jellies and jams and freshly baked hearty breads for great prices.
It is very possible to eat extremely healthy even on the tightest budget. Look for sales, cut coupons and shop around. You can do it and it is so worth it.