In my experience you just have to buy what's in season.

E.g. veggies harvested in early spring are going to be expensive in the middle of winter.

I go to local produce markets, they mostly only stock what's in season

A bit of googling shows it's not just my area.

Average prices:

Zucchini - $1.54/lb

Broccoli - ~$2/lb

Tomatoes - $2.23/lb

Corn on the cob - ~$0.50/lb (though really we should account for the cob weight)

Whole potatoes - $0.95/lb

Bone in chicken legs - ~$2/lb

And junk food:

Potato chips - $2.98/10.5oz

Big Mac - $5.17

I have a hard time believing this.

Anecdotally, I can get veggies for several meals for less than a bag of potato chips.

Nah but other glutamates are