Traded in 3G for 32GB IP4. Paid about $125 altogether. Don't think they'll be getting anymore in. A couple RS's around me said that if you were put on their waiting list them, MAYBE, you could still snag one but, for the most part, this offer is done and over with.
I bought 2 iPhone 4's, one on 11/18/2010 and the other on 11/24/2010 at 2 different Radioshack's. Since it was less than a month since I bought the phones and the price had dropped, I was able to get them to price match and got $50.00 + tax refunded on each phone. It was quite a bit of work and spent about an hour in the store because their system wouldn't let the manager price match. He had to get approval from the district manager and have their back end support people to initiate the price match manually.