Consider costs
You need to figure out what it's going to cost you to ship the item to yourself if you buy the mixer through the internet. It may cost quite a bit considering how big of a machine it's going to be. But, there are transport companies that can bring you the mixer on a truck as long as you're willing to pay for the service. Do the math and see what the mixer will cost overall. You'll probably be able to get a mixer at the lowest price if you buy it from someone that is located near you so it doesn't have to be shipped far.
When you're going to use a self concrete mixer, you need to know that it works properly. That's why you need to make sure you can get your money back if it's not going to work for you. Generally, you'll have to pay to ship it back if you have a problem so you need to make sure that you're buying from a company that sells the best mixers at fair rates. You don't want to end up with something used on your hands that no longer works or you're not going to be happy with the end result.