Shipping same day is difficult and costly.
If lets say you decided to send kindle book as gift, depending when and what time you are ordering will determine the cost and the time of the delivery. Businesses such as Amazon for example, use courier and carries, such as UPS / FedEx / DHL. However, there are problems with such big companies, as some don’t operate on weekends or work 24/7.
The beauty with the smaller companies such as Rapidus is that the latter can provide a personalized service without an extra charge and will cost much lower than the regular courier.