Several discount codes are available for tonic15.com. The best discount code available is 'FYV35', which gives customers 35% off. Another code, 'LINDA15', provides a 15% discount. Other codes include 'VIBE25' for 25% off, 'SPEEDY10' for £10 off, and 'VIP20' for 20% off. Please note that these codes may have expiration dates or specific terms and conditions attached to them. It's recommended to check the website or promotional emails for the most current discount codes.