30 tyrian schekels, at 13,8gr each = 414gr of silver. At an average purity of of 92,5% that's 
300$ of today's money. 
Judas betrayed Jesus for 300 bucks. 
Worst trade in the history of trades, rightfully so he hung himself. 

 https://image.nostr.build/2d74cb450f83a6d9081bcf9ed45a651b0abb7384a2a45e8574c3e08ee218ad56.jpg 

https://www.muenzen-ritter.de/45376-phoenizien-tyros-schekel-jahr-32-95-94-vchr-fvz.html 

 I know too little about Judas' individual situation to say anything about how important it was for him to do this. Perhaps he or someone in his family were in a terrible situation due to debt?