Ecommerce website design

I urgently need a e-commerce website developed. I am on a tight budget.

the front end I have liked are

http://www.thelightbulb.co.uk/index.php?gclid=COH9tb6eqqsCFagntAodaQzwLA
http://www.lightbulbs-direct.com/full-catalogue.aspx

I am open to the what is used but the site must be custimizable from the from and back

The website will be hosted on my hosting company and a version uploaded to my server under VMware ESX and VM Ware 8 workstation. This is to allow me to take the site to shows where Internet access is ot available.
Must be able to backup the data and transfer between servers.

Any question, please contact me