School me on shipping/costs

Depends upon what you are shipping and how far.  USPS is decent and can be worth the cost, but it depends upon if you want insurance or not.  Insure it for what it is worth, so when it is lost, you get refunded your money.  It can get lost.

I like UPS, because they are close to where I live and have places that I can get it done.  FedEx is terrible for my location for pickup or delivery, so I never use them to ship a package.  I try to never use them to deliver a package if at all possible.

You can setup an account with a credit card with UPS and FEDEX on their websites.  The shipping costs when you charge it to your account are considerably less than taking it to the store.  You can type in the size, weight and destination to get the estimated shipping costs.   

You print the label yourself then just drop it off at a UPS Store or FEDEX/Kinkos for them to ship.  It is very easy to use.

Just use ebay, they make it really easy. Once your item sells you just pick how fast you want it to get there, tell them how much it weighs and you can print a label and drop it off at the post office.

I am selling a bunch of motorcycle parts on ebay right now, bout to head to the post office and drop 2 boxes off, was really easy to get the labels thru ebay, they fill them out for you and charge your paypal account which is how the buyers paid me. All very easy and straight forward.

If you don't know how much to put down for a shipping charge on your ebay auction just search for similar items and figure out what everyone else is charging or go to usps.com and use their postage calculator, I did a coast to coast so I could get a highest price then I priced similar to other ebay ads. You may lose a few bucks on some things but you might make a few bucks on other things as far as shipping costs.