Just wanted to update on the prepaid RedCard in case anyone else was looking into them. It appears there is currently a glitch with them, where some people's cards are not recognized by Target.com as RedCards, just as American Express cards -- meaning they are not giving the discount or free shipping online. I spent over 30 minutes on the phone trying to get it sorted out, and they had no idea why it's not working.
I need my discounted Disney gift cards soonish to pay off my trip, so I ended up just applying for the RedCard credit card, which worked out fine. Was hoping I wouldn't need to bother with another credit card, but I always pay things off right away and it saves so much money, I'll deal with it! (I don't like cards to be connected to my bank account, so I didn't want the debit card) And we do go to Target regularly. So with my Target giftcards from cardpool I finally got this stuff working!