Priority mail has a higher price, but it’s faster. First class is less expensive and slower, but carriers often deliver first class packages within two days.
USPS priority mail takes up to five business days from when you’ve been notified that your parcel has passed through customs until it arrives at its destination; USPS first class takes between 2-3 business days after you’ve been notified that your packet has cleared customs. Both are usually delivered by the United States Postal Service, although there are some exceptions for Air Mail Parcels and Parcel Select which are serviced with other carriers like FedEx or UPS domestically or based on the area they’ll be delivered internationally in order to speed along delivery times.