At https://www.apress.com/subscription, APress are offering unlimited access to their library of books at $199 for a one year subscription.
I am impressed by their system which allows access to all their epub format books. The rendering as web pages is very clear. For a limited time viewed e-books can be purchased for $4.99!
They operate a 24-hour free trial system (you are not charged if you cancel within 24 hours). If searching for books on say lightswitch, enter “lightswitch @epub true” into their search box and click “go”.