Apple Cinema Display HD (23-inch DVI) without the power adapter?

I am in the market for an Apple Cinema Display (23-30 inches). Many of the monitors I have found on Ebay or other stores are sold without the 90W power adapter.

Is there a similar adapter that I can purchase? Can I dual display without having to plug both of the monitors into a power source?

Can I buy a monitor without the power adapter and be able to use it without having to purchase an Apple 90W adapter? Are there similar / cheaper models?

Thank you so much for your help.