Are these “Must-have” WordPress plug-ins? (Cyber Monday)

.
Are any of the Envato Market cyber Monday plugins a must have (some are 50% off so would love to take advantage)
https://envato.com/cybermonday/

I want to make a membership based website. Is “ultimate membership pro” a good plugin? Is there better or free ones? I’d rather pay for quality so this looks like a good grab: https://codecanyon.net/item/ultimate-membership-pro-wordpress-plugin/12159253

Is Premium SEO pack worth it? Or is there free ones that do the same? I’m an SEO newbie so…

Are these “Must-have” WordPress plug-ins? (Cyber Monday)