Shopping cart coupon/discount code process

I want to add coupon/discount code to custom asp.net site that alrea开发者_Go百科dy has a shopping cart. I'm looking to see if there are any resource on best practice to implement this feature in asp.net. There might also be a third-party product that is out there. Any suggestion would be appreciated.

Jamal

---

Coupon/Discount codes are both easy and tricky based on how it is implemented. Few questions which may help you are as follows:

• Is the coupon code item or group / item type specific ?
• Is the coupon going to be user specific if not then is there an expire date set ?
• If your shopping cart already has bundles with discounted item then is the coupon code still going to work ?
• If VAT and TAX are calculated seperatly in the shopping cart then does the discount applies before the VAT and TAX are calculated or before?
• Are users aloowed to use the same coupon more than once ?

Other considerations to keep in mind:

• In bundle, the user should not be able to apply the coupon code and remove an item.
• The user may frequently use the back button in the browser and so the coupon code must be valdated and stored in the database only when payment is complete successfully.

Hope the above helps.