How to determine cheapest way to ship large item when creating a listing?

[thisisall1word]

Want to ship a 10 lb item with 42" by 17" by 6" dimensions. In the listing form I can't find any way to find the cheapest way to ship this. It just asks me to select a shipping policy. I just picked USPS priority without knowing if this is cheapest for the buyer or not.. Seems weird they don't make this intuitive? Or am I missing something? Here's the listing and you can see the shipping estimate is ridiculously high for a 10 lb item:

https://www.ebay.com/itm/325598650099

Here's what I see on the listing form:

[nobody*s_perfect · Accepted solution]

The eBay shipping policies setup is the farthest thing from intuitive!!

To compare prices, it's more convenient to use eBay's separate shipping calculator tool. Note that it has options to display either the retail ("in store") price or the online ("eBay") price.

http://www.ebay.com/shp/Calculator

The price shown in your listing is high because USPS has surcharges for packages that are over 1 cubic foot (1728 cubic inches) and/or over 22 inches long, so  those fees to bump up the postage cost compared to what a smaller 10-pound package would cost.  For USPS, probably Parcel Select Ground will be the lowest cost.   Other services such as UPS and FedEx also charge more for larger packages.

[thisisall1word]

Thanks, wasn't aware of this calculator. Strange why they don't put a link to it on the listing form? Using the calculator I found out that Fedex was a third the price of USPS ground!

The calculator also seemed rather dumb as it showed me options for priority flat rate envelopes even though I inputted my dimensions which all exceed any flat rate envelope..

Classic examples of billion dollar tech companies making core features as difficult as possible for the users...

[nobody*s_perfect]

I don't use FedEx or UPS but I have seen plenty of threads bemoaning surprise surcharges that appear after the package has been delivered. You might want to search   out those threads or start a separate thread to ask about potential surcharges for large packages shipped with FedEx and UPS.

[thisisall1word]

I've used fedex before and you have to make sure the box dimensions and weight are exact. I think the upcharges come from people who undersize the box dimensions  and/or underweight it.