There's a few options available so hopefully at least 1 or 2 work out for you.
Easiest is PayPal, straight cash. But if you're willing to work a little more you can make your SB go a little further.
If you do PP then you can use your CC that earns cashback or points or discounts to buy the Disney GC and reimburse yourself.
Each month the first $25 GC you redeem for is discounted from 2500sb to 2200sb. This does not apply to PayPal. So most folks cash out for Target,
WalMart or
Best Buy where you can use a GC to buy another GC.
Take that another step further and if you have a Sam's Club membership (or know someone who does) you can get discounted Disney GC's there and use the WM GC's to pay for them. Best Buy also participates in Swagbucks and Shopkick rewards programs. So you scan your QR code at best buy and get additional rewards off the free GC's you're buying. Swagbucks has a promo at the moment with Best Buy where in store purchases of $50 or more get a 500sb bonus on top of the % back (currently I think it's 2%).
Spend 4400 sb to get $50 in BB GC's, buy a $50 Disney GC with them and scan the QR code, get back 600sb to work on the next redemption

(4700 if you don't want to wait 2 months to cash in)
If you haven't already, following along with the Disney Gift Card thread in addition to this one helps figure out how to maximize the savings. And you'd know that not all BB, WM, Target are easy conversions. While the corporate policies might be acceptable to buy GC>GC some individual stores block it. So if you haven't tried before I'd start small and make sure your store allows it before you get stuck with a bunch of GC's you can't use on something else.
ETA: Wow I have to think and type faster, I think everyone made all the same points while I was still typing! Great group