Generally, the buyer pays shipping so the business owner shouldn't incur a lot of shipping costs unless they run free shipping offers frequently.
A lot of inexperienced wahms will jump right onto the gimmick wagon & lose money by offering specials like free shipping without taking into consideration their profit margins, packaging materials, & time.
UPS & Fed Ex charge monthly or yearly fees if you're a business owner & sign up for their daily pick ups. You can check their websites & call a rep for more information. These fees are passed a long to the consumer in a round about way either by charging a handling fee (which a lot of people don't like) or by simply making sure your retail prices on your products make you enough to not only pay the bills, overhead, and make it worth your while, but also ensure that you aren't losing money on shipping costs.
Online post office services can save you loads of time, but also add a cost to your efforts. www.stamps.com
allows you to print your postage without having to stand in lines at the post office. www.shippertools.com
allows you to print labels & get free delivery confirmation but you still need to stand in lines at the post. Time is money, so don't forget to account for that as well.
While dropping off packages at a UPS or Fed Ex place may seem more economical - you need to take into consideration the wear & tear on your vehicle, the time it takes from your day, how many kids you have to bring along & whether it wouldn't be worth it to simply have UPS or FedEX come to your house instead. It all kind of depends on the volume you do.
You can get free labels through UPS & free shipping supplies through USPS. However, the packaging you use to ship UPS or Fed Ex should not be Priority packaging turned inside out, that's stealing from the post office. Recycled packaging also may seem like a good idea in the beginning but again if you do high volume shipping - digging through recycle bins & driving to grocery stores for boxes will quickly feel like a big burden. We buy our boxes wholesale locally but there are lots of places online you can buy in bulk & have them shipped to you. We need a large variety of sizes, but often wahms who are shipping just diapers, slings, and smaller items can get away with poly jacket envelopes or tyvek envelopes.
Hope this helps a bit,