Please send me 500 at $1 USD each. I know I can quadruple my money on those!
Just register account on taobao and search. I believe you can find a good deal.
May be not 1 USD, but close to that.
If you need more cheap you're needs to look direct supplier in China.
But note, you will get performance for the price and not more.
If you pay 1 USD, you're get performance for 1 USD.
But it doesn't means that payment 30 USD for the same thing will increase performance