For non-professional application it’s not the cheapest option, however on the used marked I payed 82 € for my last ethernet bus cupper plus 3 digital IO terminals. Often used Beckhoff variants of the functional identical terminal are a little bit cheaper than WAGO – might have to do with the different market segment they targeting. In a professional setting the hardware costs compensate often easily for saved working hours in debugging flimsy screw terminal connections and dubious firmware flaws. Also, the cheap options often need more than 5 times the control cabinet real estate per IO, witch alone can compensate for the higher price.