when they say " only $4 a trade" on online stock broker sites what does this mean?

[J W]

does it mean if i buy 20 stocks for 40 dollars do i have to an extra 80 dollars or four dollars everytime buy and trade those stocks

[talbot983]

$4.00 a trade. there may be other cost invloved as well. any sec fees. possible higher cost on pink sheet stocks (
penny stocks)
and $4.00 when you sell too.