Sometimes the best first step is making a healthier alternative at home. Few food items that are low cost, pre-packaged, ready to eat, will be healthy.
You could skip the frozen or restaurant pizza and make your own with low sodium sauce, use cheese lightly, add healthy toppings.
For cereal instead of the typical sugary stuff opt for oatmeal with whole fruit or nuts. Even Cream of Wheat is better than sugar flake cereals.
It's not that you have to get rid of all that you like but the goal is to find alternatives with healthier ingredients.
It will take effort on an individuals part to eat more healthy but it doesn't have to be more expensive. I like to make dinners that last a few days. I make a quinoa and bean chili that I really enjoy. It takes me about an hour an lasts for three days. It has quinoa, kidney beans, diced or crushed tomatoes (low sodium), onion, vegetable or chicken broth (low or no sodium), corn and a few spices.
The drive to do this has to be there. Healthy eating takes some time and effort but, at least from my experiences, it's worth trying. Once you know dishes you like and how to make them the easier it all gets.