What Dave says ...
Buyers who say they would be willing to pay only so much for shipping IMHO are just full of you know what ...
Allowing the seller to recover his FULL shipping expenses would only be fair, but NOT more than that, except maybe a $ or so for extra packaging, padding or whatever.
Some sellers really go overboard in what they would charge for "handling" (hey, funny ... I guess nobody would mind receiving their LPs in used SECONDHAND record mailers if this helps reining in shipping costs, and proudly boasting some blurb like "all LPs will be shipped in a BRAND NEW mailer" ... hey, big deal ... especialy if this means shelling out separately). And as long as some sellers are not even afraid of shipping their records in secondhand 12in PIZZA BOXES (!!! happened to me more than once with sellers from the U.S.) there are a lot out there who would need to clean up their act too.
Not to mention those who charge airmail but ship sea freight, those who go wildly overboard in stating shipping prices beyond all reasonable limits and are NOT EVEN WILLING to listening to pleas from buyers (who tend to gain much experience with what shipping rates would be best) to go for the most economical (and tried and tested) airmail rates. Beats me every time, for example (when buying printed matter), how often I have to tell U.S (NOT "domestic only") sellers that they DO have something like Global Priority Flat Rate envelopes which are FAR more cost-efficient than any airmail or weight-sensitive rates. Under what pebble have these fellers all been living all these years, I wonder???
US sellers like myself who use the USPS system no longer have the option of surface mail. Been gone for a couple of years now. Re: Global Priority Flat Rate, the box size to fit an lp would make it Large Flat Rate, and cost a minimum of $58.50 - there are no envelopes that fit the the lp, only boxes. I have not looked into the UPS system, however.