After asking my daughter why she liked to play so much in the Lego shop and not at home with the legos, she said because there she could build in top of the lego ground and have a box near the table with the legos. Since her birthday was arriving, we decided to improve her lego place with a small and cheap solution based on an Ikea Lacks table we had lying around in the storage and a LEGO X-Large Gray Baseplate (628) of 15 inch (~38.1 cm).
She seemed quite happy with the table and now plays much more with her legos :)