thanks for your large requirement.
firstly I must say sorry, the price can't lower. because there's no enough stock availible in market and several customers are waiting in line now.
(used tanks are not have enough availible in market usually, if have enough, the price will be lower, and opposite, is higher.)
1, if you need same cover with sample, we need do new for you, $8.oo/pc. and need cleaning and package with plastic, also need added extra $3.50/pc.
so total amount is $41.00/pc ($29.50/pc + $8.oo/pc + $3.50/pc>.
(and because of used tanks, so the cover can't confirm is the same, generally speaking has 3 types, I told you before.