A canny seller will simply send these items as an air letter for around a dollar, no customs, no tracking, no fuss.
The canny seller will keep as much as possible of the total amount the buyer is willing to pay, in their own pocket.
The innumerate seller will charge $5 to avoid the chance of losing $1, which is obviously irrational, but distressingly common.
You just need to find the sensible sellers. They are more likely to be better sellers in all other respects as well.