If you're looking to spruce up your home with a fresh coat of paint you might be wondering what the difference is between $20/gal and $50/gal paint. Both will do the job, but lets look at the pros and cons of each. Lets preface this with that you always need to do paint prep beforehand. Fill in those cracks, nail holes, dents, and dings first. Then sand them down.
With $20 paint you will always need to do 2 coats of paint, and maybe 3 coats if you're covering a dark color. When I first started rehabbing properties I started with the cheapest paint to save money. My theory was, if I'm going to be doing 2 coats no matter the quality of paint I purchase, why buy the expensive stuff? In the end I found myself doing 2 coats plus touch ups in thinner areas, and sometimes 3 coats. That's a lot of extra time. When the walls get scuffed up the cheap paint does not clean easy either. My first home had cheap builder grade white paint and the entryway would always get hand prints on it from people putting their hands on the wall to take shoes and boots off. When I would take a washcloth to it to clean it the washcloth would be white from the paint coming off the wall. We don't want that!
Each house I've fixed up I have progressively kept going up in paint quality to the next price point. Now I always use the higher end stuff that retails for $45-$50/gal, every time. With paint discount promotions or asking for discounts you can get the good stuff for $30-$35 per gallon at Porter or Sherwin Williams. Big box stores also do sales several times per year. Paint is usually on sale somewhere, and I have not really found a preference on one brand, the high quality paints are good everywhere in my opinion.
With good paint, if you are just painting a room that does not vary much in color you can get away with one coat (plus maybe a few touch ups) by putting it on heavy. But ideally it does look best with 2 full coats of paint. For covering up walls that have more blemishes, FLAT paint is always best. Other types of paint such as semigloss, eggshell, satin, etc have a little bit of gloss to them which makes imperfections show more, although they do wipe down easier.
Happy Painting!