International point of view
How is everyone shipping their for sale items?
I sent a 3.5lb package via UPS @ Pakmail and it was $16.85.
At the risk of being redundant to other comments, and possibly off-topic (as you probably wanted information about intra-USA shipping), here's a few points from an international buyer point of view.
0) UPS/DHL/FedEx are a no-go most of the time. Way too expensive. USPS is the preferred way in many cases.
1) shipping materials (boxes/envelopes) can be obtained for free from your Post Office
http://shop.usps.com/webapp/wcs/sto...=13356&parent_category_rn=11820&top_category=
2) USPS can also pick up the package from your house for free:
https://carrierpickup.usps.com/cgi-bin/WebObjects/CarrierPickup.woa
3) postage can be paid online, you can print out all necessary documents (including Customs form) from the web. You even get a discount of 5% (international priority) for the postage!
https://sss-web.usps.com/cns/landing.do
4) International Priority or First-class Mail seem to be the best balance between price and usefulness.
5) You can request Delivery Confirmation to make sure you are covered for "loss" of package.
http://www.usps.com/send/waystosendmail/extraservices/deliveryconfirmationservice.htm
6) often a good way to ship internationally is a prepaid, flat rate envelope for just 11.95$, good up to 1.8kg (4lbs)
http://www.usps.com/international/prioritymailinternational.htm
7) if it's something larger, you can use prepaid, flat rate box (3 sizes available, starting at ~40$)
Hope that helps a bit
I've bought many things from US. The highest I remember paying was around 55$ for a heavy package (~10lbs box), with tracking and extra insurance. Small purchases of flashlight accessories (reflector/adapter/lens) were as low as 3.8$ (4oz packet, International First Class with delivery confirmation).