I have used the target red card stacked with the pharmacy 5% card multiple times for large amounts. I pay for everything disney related this way, my DVC dues, entire cruises, rooms, passes, meals, shopping. A penny saved is a penny earned, so I'll take every one I can get! I have only run into a few problems, and have discovered workarounds for them.
1. I try to make a large purchase to cover my anticipated needs when I have a pharmacy reward. (I put money aside) The red card has a "limit" attached to it of about 500, even though it is tied to your ATM. This requires you to ring them thru as multiple purchases. This may set off their fraud activation system. Once, they had us call the red card number to confirm, another time the manager came over and just let us use our regular card, and hand entered the discounts.
2. DVC is offering a steep discount on PAP's right now. The regular DVC member number will only allow you to use 2 GC's at a time, but if you tell them ahead that you are using multiple GC's, they will transfer you to another number that will do it.
3. There have been times when I wanted to make a purchase and had no pharmacy reward. What to do???
If you link to the target web site via upromise, you can save that way. The only down sides are that you can only buy 3 cards at a time, and it also takes a long time for the money to get transferred over to upromise.
4. Make sure that you save both your receipts AND used GC's. As others have mentioned, there have been some inactivated GC's. I have had this happen. If you have saved your receipt, they can fix it quickly. Also remember that returns go back on GC's so remember to keep them