The expression, 'when you go cheap on ...' refers to yet another expression. That expression being, 'You get what you pay for'. Both expressions assume that when someone pays for an item, or a service, the more expensive the item, or service, the more reliable, or higher in quality, it is.
Most would agree that this is considered a "Maxim" of life and is an accurate rule of thumb or generalization. This maxim might not always apply, but it holds true for many things.