ALL INFORMATION FOUND HERE
**https://www.usps.com/ship/priority-mail.htm** 
 
I round up to nearest $5. 
 
Features & Pricing
Fast delivery time: 1-3 Business Days1
Free Package Pickup3 service at your home or office
Includes USPS Tracking®4 and up to $100 of insurance5 with most shipments6 (restrictions apply)
No surcharges for fuel; residential or rural delivery; or Saturday7 delivery
Flat Rate and prepaid pricing (retail only) available
Prepaid Forever Priority Mail Flat Rate. Except for Priority Mail Flat Rate packaging, Priority Mail prices are based on weight and zone. With Prepaid Forever Priority Mail Flat Rate, you get the same Flat Rate pricing with the added convenience of Forever® postage.
USPS Label Delivery service: Even if you don't have a printer, you can still ship online using enhanced Click-N-Ship—for an extra $1.25 per label, we'll print an outbound label and deliver it to you. (Businesses can also request return labels for their customers.)
Service
Prices
Priority Mail Express®
From $31.55 at the Post Office™
From $27.35 for Commercial Pricing
Priority Mail Express Flat Rate Envelope
$32.00 at the Post Office
$27.90 for Commercial Pricing