This is definitely known as the poor man's snack but they're delicious and so good for you. I always keep a few cans on hand. I usually enjoy them with some whole grain crackers but people prepare them in all sorts of ways (sandwiches, salads, with rice). Sardines, smoked herring, tuna -- all reasonably priced, full of nutrients and easy to enjoy.
2. Peanut Butter
Nuts tend to be expensive. A 16oz jar of peanuts is $5. A 16oz jar of peanut butter is $3.50. Peanut butter is more versatile, tends to last longer than whole nuts, is filling and inexpensive. Just make sure you get an organic brand that isn't loaded with preservatives.
3. Bell Peppers
Instead of potato chips I try to snack on healthy things. Not always easy to do, but bell peppers are a great healthy snack and they won't break your budget. Veggies in general can be pricey especially if buying organic (which you should) but one bell pepper only costs about $1.50. Cut it into slices and store it well, I can spread one pepper into two or three snacks. A small bag of chips costs at least $.75 and you eat the whole thing in one sitting, not to mention all the salt, grease and calories.
When I need something salty and greasy I usually make popcorn. I pop my own kernels on the stove. A bag of organic popcorn will only run you a couple of bucks and can make around seven bowls of popcorn. A bag of already popped, packaged popcorn will run you the same price, is less healthy and will only make about two bowls. So you do the math. Making your own popcorn is not only healthier but more cost effective as well. Tastes better too.
A bag of dry beans costs $.99, are delicious, healthy and a good addition to any meal. There are so many good bean recipes out there and it's really a nutritious staple, especially for vegetarians. The only thing is, if you get dry beans they take a while to cook.
I guess the moral of the story here is that if you can eat healthy for less, but it takes more time than just popping something in the microwave or ripping open a bag.
I tend to appreciate the time it takes, maybe that's just me but convenience isn't always best. Sometimes (meaning always) slow and in the moment is better.