Some items (hoses, QCs, name brand parts) are cheapest price including shipping for me.
Other items (soaps, speciality parts, repairs parts) I go with the best quality available, price less of an object. Basicly its cheaper in the long run to buy the best.
I do try to spread my dollars around to good suppliers who have been helpful and offered customer support, got to keep the good guys in business.
I will not deal with some companies who offer cheap prices, cheap products, and bad customer service (no names mentioned-- you know the company)