We recently got asked a question about tiered shipping rates by one of our clients in the US:

We need to set up an online store that sells a single product (a book). They are $19.95 each, or $14.95 each if you purchase 5 or more.
An additional Shipping & Handling charge of $4.95 for the 1st book and an additional $1.00 for each subsequent book will be applied.
We also need to charge sales tax for Colorado residents only.

One way you could approach this using WP e-Commerce is as follows.

1. Tiered Product Pricing

Tiered Pricing in WP e-CommerceIn our example we have:
1-4 books: $19.95 each
5+ books: $14.95 each

WP e-Commerce supports this tiered/table product pricing model. This is implemented via Dashboard -> Products -> Products -> Edit.

You enter the base price (in this case $19.95) in the price field.

Further down the page there is a table rate price section. This is where define a price of $14.95 each for 5 or more products.

2. Variable Shipping and Handling Rates

Although WP e-Commerce can’t directly support the tiered shipping rates, It does have a “table rate” shipping method.

Following our example we could define something like:

# of books    Order TotalShipping Price
1 book$0 and above$4.95
2 books$29.90 and above$5.95
3 books$59.85 and above$6.95
4 books$79.80, which is more than the next teir below due to our 5 book rate
5 books$74.75 and above$8.95
6 books$87.90 and above$9.95

WP e-Commerce Table Rate ShippingTo set this up in WP e-Commerce, go to Dashboard -> Products -> Settings -> Shipping -> Table Rate -> Edit.

Set up the layers as per the screenshot to the right.

Note: You may wish to add more layers to cater for situations where people order more than 6 books.

This setup almost satisfies our shipping rules, apart from the 4 book scenario where the customer would be charged $8.95 for shipping instead of $7.95. In our case this was an acceptable trade-off.

3. US state-based Tax

WP e-Commerce US Tax Set UpWP e-Commerce also supports charging different sales tax amounts for different US states.

We set this up via Dashboard -> Products -> Settings (see screenshot to the right).

Once configured, the online store works as follows:

The customer adds product(s) to their cart, then once they go to the checkout they choose their destination country/state. If they choose Colorado, 10% sales tax is added to the order total. This effectively means that the prices on the website don’t include tax, and tax is added during checkout where appropriate.

So there you have it!

More information: OM4 eCommerce