userid = Your shopping cart username
product = Description of your product
price = Price (without Currency enumerator: $, £ or whatever)
or
discountpr = Using a quantity discount
productpr = Set both the product and price field in single field separated by a colon (My product description:9.99)
qty = a quantity (default = 1)
return = www.your_co.com/your_page.htm (default = none) for a Continue Shopping button
units = a weight or other value for calculating shipping (default = 0)
lg = a language other than your default
currency = currency number for multi-currency payments
tax = % rate of sales tax for that item (default = 0)
scode = a stock code or SKU you would like the cart to store for you, it should be unique for each product
coupon = a discount coupon
sd = your own session data
thumb = filename of a thumbnail image to appear beside the product in the cart
producturl = URL to make a link back from the cart to a particular product
noship = 1. Overide the option to automaticaly set shipping units to the same as the price for that product
noqty = 1 , 2 or 3. Turns off the carts' quantity box
The values can be set to: