You can actually just put the letter in your mailbox. You don't have to take it to a dropoff.
If you're willing to drop it off, they also do same day for $4 for packages under 5 lbs inside a local region. They'll pick it up and drop it off just about anywhere in the country next day for basically the same cost.
Your point stands, but the USPS is a logistical wonder.
You can actually just put the letter in your mailbox. You don't have to take it to a dropoff.
If you're willing to drop it off, they also do same day for $4 for packages under 5 lbs inside a local region. They'll pick it up and drop it off just about anywhere in the country next day for basically the same cost.
Your point stands, but the USPS is a logistical wonder.