Some advice to those mailing items. The Post Office will NOT help you get the lowest rate, maybe if you ask, maybe. If your manual will go media mail, or fit in to a Flat Rate Envelope, they're not going to go out of their way to help you. It's also not well known to some people that printing postage online not only gives you a dang good discount, some features like Delivery Confirmation are free, so is email notification. You don't have to use the USPS web site to print postage, you can use a PayPal link I've bookmarked which will do everything: https://www.paypal.com/us/cgi-bin/webscr?cmd=_ship-now
Let me give you this example:
A pinball manual weighing 1.3 pounds shipped:
1. $2.98 Media Mail online
2. $3.18 Media Mail online with Delivery Confirmation
3. Media Mail is not available online via USPS
4. $5.05 Priority Flat Rate Envelope with free Delivery Confirmation online
5. Priority Mail Flat rate Envelope is not an option online DUMB
6. $6.85 Priority Mail from my area to Texas, with D/C
7. $8.19 Priority Mail from my area to the West Coast, with D/C online
8. $9.50 Priority Mail from my area to the West Coast, with D/C walk in
9. $11.25 Worst case Priority mail across the country
Anyway, I ship a LOT of packages, most of it US postal. If you have any questions, glad to lend you my input.