If you are like me, most days it's a pain to go to the post office to mail a package. Doing it online is a great solution if you have a scale that can weigh in ounce increments. If you've ever tried to do this through the USPS web site, it works okay. I say just okay because they don't give you all the delivery options that you would have if you were in the post office buying postage. There is no First Class or Media Mail delivery option. These options, while they take the longest, offer the best rates. But, hey, you didn't have to get in your car and go to the post office!... Right?
However, there is another, less-advertised option. If you have a PayPal account, you can use that to print first class or media mail stamps! Here's your link to start online shipping with better prices and more options: https://www.paypal.com/us/cgi-bin/webscr?cmd=_ship-now
So, about how much might you save using First Class over Priority? I checked prices on a large envelope weighed 2 ounces for this case study. Cost to ship First Class? $1.58. Cost to ship Priority? $5.05. That's a savings of $3.74.
The final word: If I'm going to ship at home, I'm doing it through PayPal.