Unfortunately, too many websites use poor quality images which not only portray an unprofessional feel but may also not give your products and / or services the credit they are due.
If you are selling paintings for example, and the images are pixilated, you cannot zoom in or the aspect ratio is incorrect (so the image appears stretched) then people will be put off using your website and will more than likely go elsewhere.
The cost of a professional photographer varies but you can usually get one for half a day for between £100 and £200 pounds. This may be plenty of time to take all the pictures you need. Remember if you are paying for a half or full day, to ensure you try and get as many images as possible such as staff members and premises as well as products / services as you never know when you may need them.