Fresh is best

Using fresh ingredients is always the best options.
Example: Fresh or Frozen vegetables have little if no sodium, 
Canned Corn - 270+mg of sodium, fresh or frozen - 0mg.
How you cook it makes a difference also, don't add salt to water or to corn while cooking. Use only 2T of Salt-free Butter, a sprinkle of sugar . and as Rachal Ray would say.... Yummo!

Not all frozen is sodium free. Lima beans for example can have up to 200+ mg of sodium per serving.

Veggies are a great way to stretch your food budget and fill your plate.
Potatoes - high in potasium and low sodium. Mashed potatoes can be filling and healthy.
Boil with no salt in water, drain, add 2T of unsalted butter, and 2T of natural sourcream this gives you a rich mashed potato with lower than 20mg of sodium for a cup serving.

if you can use fresh jalopenos and tomatoes for your salsa in a food processor, you get a healthy snack. add garlic, onion, and fresh peppers... mmm.!

read labels, canned vegetables and fruits are always higher in sodium to preserve them. You might think you are healthy but not... also, cost wise, you pay for a lot of water in canned. buy storebrand frozen and save money. 

a piece of boneless, skinless chicken breast grilled with lemon juice and pepper along with a baked potato with natural or regular sour cream and frozen corn -unsalted butter on both is filling, healthy, cost conscious, and under 300mg of sodium.