We have an ecommerce system which needs a modification - this is NOT osCommerce, XCart, Magento.
We need to add in a field at checkout which will allow a user to enter an affiliate ID to assign that purchase to an affiliate - presently the user can access affiliates via a URL but we want to limit them to manually entering the affiliate ID in the cart.
More details and link will be supplied to those showing ability in this - we would prefer to work with providers we have worked with before.
No milestones, work live on our server, payment when completed and checked by client. Don't bother bidding unless you agree to this payment term.
3 freelancers are bidding on average $8/hour for this job
This sounds like it will be easy for me to accomplish for you. Have extensively customised shopping carts in the past and have lots of experience modifying other people's php code.