You will be able to add as many Reward's that equal your Reward Points balance. As you earn more Reward points, you will be able to add more Rewards to your Basket.
In some cases, you'll only be allowed to claim a maximum number of certain Rewards. This is to ensure the entire Advocate community gets fair access to all Rewards. For Rewards that have a maximum cap set, you will be shown in the Reward Shop how many you are eligible to claim. Once you have claimed your allowance, you will no longer be able to add any more of that Reward to your Basket.