Starting a intercompany trading network

Hi,

I would like to set up a intercompany virtual trading network. The thing is this. The company I work for has many affiliates in Europe. All these affiliates have different excess stock of IT hardware. I would like to set up a system on out Intranet that enables the affiliates to sell and buy from and to each other, something like eBay.
Does anybody know a system that can do this job and is not too expensive?
Please advice.

Thanks,

Maurice