Whilst a free or cheap design service may be offered to you through landscape construction companies, this can be a false economy.
Using a professional designer will make sure that materials are carefully chosen to suit you and your design requirements, and that experienced and trusted contractors are used at all times. High quality plants can be sourced from nurseries, and the construction can be overseen to ensure that the garden is built exactly as designed. Any issues can be sorted out on site, with your designer and contractor working together to ensure an excellent outcome.
Professional garden designers know what will work in a garden, and how to avoid the pitfalls seen in so many designs. You want your garden to be a comfortable, relaxing place, and with the average cost of hiring a designer being approximately 10% of the cost of construction, the investment will be well worth the peace of mind.