High quality, inexpensive cat food?

Is there such a thing? My cat really needs to lose some weight because I am starting to get concerned about it. The vet has never said anything about it, and even when I ask if he's too fat, she doesn't seem too knowledgeable about cat nutrition, though she is very smart with everything else. I have done lots of research from a very good site, but the only examples it offered were expensive food that had to be delivered to your doorstep, frozen. I would like to feed my cat wet food that has no grains since they are unnecessary and no by-products. Does anyone have any ideas or recommendations? I care about my cat dearly so I would be willing to pay a little extra for good-quality cat food, but some foods just have outrageous prices. Thanks so much in advance!