Quote What is the difference.? Do i need both?

You didn't tell us what you plan to do.? Although the sale of both is a good deal at $40 (US).

PerfectCam is used to help you look your best during video conferencing using one of these:
Supported Video Call Applications
U-Meeting
U-Webinar
Skype
Skype for Business
Google Hangouts

YouCam can get you with looks/backgrounds, etc. You can read the sales literature as well as I can.

Take a look here on what the combination sale gives you.

There is a free trail that you may want to download and run (note: if you decide to buy, you have to uninstall the programs to better install the pruchased programs. .
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BoilerPlate: To posters who ask for help -- it is nice to thank the volunteers who try to answer your questions !
Anything I post unless stated with a reference is my personal opinion.

Many thanks Stevek for your Explaination. I think I do not need both of them.
I never make Video calls. Iwill delete both from my Laptop.