I normally use TCG Market prices as a baseline as I plug trades into the MTG Familiar app with market set as values.

::Shipping plans:: Flexible
All PWE use non machinable USPS stamps.
$40 and under will be sent in a PWE,  unless I feel the cards being shipped (quality/quantity) require tracking then they will be sent in a bubble mailer.
$40 or more is when I look at moving to bubble mailer with tracking.
Anything over $100 will have insurance.
Plans can be adjusted communicating with other traders.