关于讨价还价的~请各位高手帮忙中译英,谢谢!

把语序调整了一下,另外建议lz不要使用"无利润可言"这样的字眼,老外对这种说法不是很感冒
I'm sorry to inform you that this is the best price we can offer, comparing with the previous quotation for these 2 products, we've lowered the prices as much as we can, there won't be any profit if we lower the price again. Pls refer to the attached invoice and issue the L/C accordingly.