Small to medium sized online shops (up to around 100 products) can be built with Shopify or the WordPress Shopp plugin. Both solutions look great and are affordable and have all the basic funtions you will need to run an online store, including configurable options for products, product sales tracking and customisable shopping baskets and checkout.
Simple PayPal integration can be used for websites that need to sell services or a very small number of products. You can have a PayPal button designed to match your website, so the integration appears seamless.
Online shop built with Shopify. Customers are able to select cake flavour and specify icing colours, decorations and delivery date.
PayPal can be used if you are selling services, such as courses, events, workshops.