If this helps, I did exactly what you are considering last May for our trip to WDW. Bought the emailed gift cards from Sam’s Club because of their relatively lower cost, and then logged onto my account on https://www.disneygiftcard.com/ web site, as PrincipalTionker & SamRothein suggest, where I was able to transfer those emailed card balances to another physical gift card I also bought at Sam’s Club, which I used (like a credit card) when we actually went to WDW. If this link works, here is my post from last April where folks on this web site helped me figure out how to do what I just described. egift cards
Good luck.