Are there any beauty devices that are genuinely effective, not just the advertisements?

I know I shouldn't compare this to a dermatologist's office, but I'd appreciate recommendations from anyone who has used beauty devices that showed even a little bit of effect! Maybe it's because I haven't used them consistently, but I couldn't really tell the difference even with the devices my friends said worked for them. Please advise whether it would be better to save the money on these devices and get treatments at a dermatologist instead, or if I should just stick to consistent at-home care!