I really rarely use cookbooks. We are really just meat and veggie or easy pasta recipe people. Most of the recipes I do use come from others, not cookbooks. I definitely don't get into elaborate recipes or anything. But when I do use them, my favorites are the one's I got at my wedding showers 15 years ago.
I have the Better Homes and Gardens one that I like also.
The Four Ingredient Cookbook by Emily Cale and Linda Coffee (super simple stuff)
The only one I ever really use anymore would be the one my grandmother gave me that her homemakers group made compiling all of their favorite family recipes. I like this one because it has all the stuff she used to fix in it.
As for frugal ones, I kinda liked these few:
The Tight Budget Cookbook book by Heidi Smalheiser
The Use it Up Cookbook by Catherine Kitcho (I am bad about letting things go to waste sometimes
)
Oh, I saw this one the other day, had to look it up again, but you might like it.
The $5 Dinner Mom Cookbook by Erin Chase.