That 18 bucks only covers the actual plastic pump and a couple of other small parts. It's sold as a "spare parts" kit. Point it fact you can buy parts for the entire machine if you wanted.
Like I was saying though, that guy who works at the repair place where I buy the parts from told me that since the Big Box stores started selling these machines, the quality went down as big box stores don't want to pay a lot for them in the first place. So where in agreement there.
I think it all boils down to what your buying it for. Most any stuff sold today no matter what it is isn't really well made anymore unless you spend up.