Hi Col,
What do you intend to carry in the baskets? The weight you want to carry will largely determine what basket is appropriate for you. Baskets can vary greatly in terms of the material they are made of and their recommended weight capacity. It terms of attaching a basket to your bike, most are extremely easy to attach, and shouldn't require a trip to your LBS. The exception would be a rear mounted basket. Those baskets are made to work with rear bike rack. If you don't already have one installed on your bike, it might be good to go to a LBS for help with selection and installation. Sometimes selecting and installing the correct rear rack can be tricky depending on what available attachment points you have on your bike.