It's less than £5 a week if you shop around, I bet most spend more than that on alcohol/cigarettes/junk/other hobbies etc per week.
I could sit and complain why Sky charge me extra to have the sports or movies package, it's just a service these days alongside most things. If you don't play online enough then the value may not be great for you, but for others playing online, having "free games, discounts etc is more than enough.
For the money I pay, I get way more back even if I don't like every "free" game given as part of PS+.