Here is the code snippet by which we can create Magento shopping cart price rule, i.e the rule which is applied on shopping cart while customer add his/her product to shopping cart.

shopping cart price rule can be divided in 3 parts
1. Information of the rule
2. Condition that will be applied on the rule.
3. Action that will be taken.

$name = "cutom programmatically created rule"; // name of  Rule
$websiteId = 1;
$customerGroupId = 2;
$actionType = 'by_percent'; // discount by percentage(other options are: by_fixed, cart_fixed, buy_x_get_y)
$discount = 10; // percentage discount
$sku = 'RBT67'; // product sku
$shoppingCartPriceRule = Mage::getModel('salesrule/rule');
$skuCondition = Mage::getModel('salesrule/rule_condition_product')
try {
} catch (Exception $e) {