Amazon prices change constantly. Even minute-to-minute sometimes.<p>At least on most of the stuff I&#x27;ve checked on CamelCamelCamel, Amazon has the lowest price on something maybe one day out of ten. Which is another way they push you towards Prime; if you have Prime, setting a price alert and buying it the day the price is the cheapest on Amazon is simple (assuming you can wait). If you&#x27;re trying to combine items to get non-Prime free shipping, though, one item might be cheapest but the rest almost certainly won&#x27;t.