Hi rixride,
Depends what exactly they want the module to do, but using cmsMerchant to display second hand cars for sale along with pictures of the cars (thumbnails automatically linked to larger images) then defining prices and using cmsMerchant's 'Options' to create further details as needed is one possibility and very easy to accomplish with our module.
The cars can be sold via Check/Money Orders/Cash and/or any of the payment processors/gateways that cmsMerchant supports :D
With regards,
Barry
cmsMerchant
PostNuke e-Commerce Solution/Membership Module
WorldPay - Authorize.net - iPayment - 2CheckOut - StormPay - PayPal - iBill, with more payment plugins coming soon!
http://www.cmsmerchant.com [39]
Also possbily one of the shopping carts systems? cmsmerchant ...etc..??? Good luck