A lot of the bigbox stores have specials on the install. The fine print is you have to buy the premium carpet with the padding.
If it's a house you'll be living in for a few years, fine, pay the extra $$. However rentals are a different category. Your job and the money you make on them depends on getting the job done, and quickly.
This tutorial is tailored toward replacing carpets in rentals to save $$.
Some of the cheapest rentals I have seen don't have carpeting. They have vinyl adhesive backed squares on the floor. The owner just buys a bunch extra and replaces the bad ones when they get burned or marked, etc.
This makes sense if you have tenants that are careless, or if you think there could be a roach problem in the future. And you will run into roaches sooner or later when dealing with lower end tenancies, it's something you should be prepared for.
Remember sometimes it's not about doing the pristine job or perfection, it's about getting the job done. We laid 2 rooms of carpet in 3 hours the other night, which included prying up and replacing the moldings, and the transitions.
Git er done.