Sign up for Rival casino ewallet. Request an invite for it. They will send it to your email. Takes a long time to get but worth it. Very trusted Rival is.
Also, I have seen were all slots takes Visa/Mastercard gift cards to deposit with. Go to a store and get yourself one and then use that if you want. Very safe that way.
Below is Da Vinci's (Rival) and All Slots. Good luck and don't spend too much!!!!