I haven't done the
Best Buy route in a while because, as I've written before in this thread, the BBs near me seem to have stopped stocking eBay GCs. But with the Target development, I've been looking at different options and I noticed that BBs near me are stocking $50 eBay GCs AND THEY'RE AVAILABLE FOR STORE PICKUP OR FREE STANDARD SHIPPING (still no $25s).
In my experience, BB's website and POS system does allow GC-for-GC purchases but you might encounter an employee or manager who won't allow it. So YMMV. The other downside for me has been that your local BB store may not carry eBay GCs or have them in stock, so your funds are stuck in the form of a BB GC until you can find availability for eBay GCs (BB does sell Disney, Starbucks, and a lot of other GCs).
The upside to shopping with BB is that you can go to BB .com, search for eBay GCs, and it'll pull up $25s and $50s that you can find in your nearby stores (by typing in your zip code), add to your cart for in store pickup, or have them ship it to you -- and never worry about availability or dealing with employees who give you trouble when you try to pay for a GC with a GC. Another benefit is, similar to the Gamestop route, PayPal Digital Gifts often runs sales on BB GCs (I'd say more often than GCM runs sales on Target GCs). When you buy from PPDG, you'll get the BB GC code emailed to you in about an hour, which you can then turn around and use on BB .com to buy eBay GCs for same day pickup for a fast flip back to eBay.