I try to pick up a couple Target GCs each month when I'm planning a trip, it's the easiest way to save 5% for me.
I would warn that you should not expect to walk into Target and find $5,000-$7,000 in GCs in one trip. At least in my area, they are sometimes in short supply. In fact, last week they only had the $25 GCss and I refuse to buy those because they are a pain when adding them to Disneygiftcard.com. My minimum is $50, but I really prefer $100 increments.
Also, one other warning…in 2012, over the course of a few months, I purchased over $5,000 in GCs to pay for a cruise and I ended up getting a letter from Target warning me that if I was doing something shady, they would lock my account. I don't know what it was about that time…I think maybe I was buying too many at once. Anyway, that's when I started just buying a couple per month and saving them.