How about (100¥)? 卖（一百块钱）如何？
Don't try to rip me off. I know what this is worth. 别想宰我，我识货。（ rip sb off 表示“欺骗某人”）
It's too expensive. I can't afford it. 太贵了，我买不起。（关键时刻，跟老板哭穷。）
The price is beyond my budget. 价格超出了我的预算。 （母上大人给的钱太少，不够花啊！ ）
I’d buy this if it were cheaper. 再便宜一点我就买。
Lower the price, and I’ll consider it. 价钱低一点我才会考虑。
I’ve seen this cheaper (in) other places. 我在别家有看过更便宜的
If I buy more than one, will you give me a discount?多买一点有折扣吗？
Could you give me a discount? 能给我个折扣吗？
Is the price negotiable? 这价钱可以商量吗？
Can I make an offer? 我能讲价吗？
Can you make it a little cheaper？ 能便宜点吗?
Let's make it 30 yuan, a round number. 就 30 元了，凑个整吧。
30 yuan is about as high as I can go. 我最高就出 30 元。
I can get a little cheaper at another place. 我能在别的地方买到更便宜的。