I want to buy 80 pieces the first time, the next time I want 
more pieces

What is your price, the best offer I have got is below. 
For your perusal. 

14inch cost US$16.5 
16inch cost US$22.0 
18inch cost US$28.0 
22inch cost US$31.0 
24inch cost US$36.5 

If you order 80pcs, the shipping cost is 190$. 
Your early reply will be highly appreciated. 
Can anyone get me better price? 
I want long term relations with the best company