With a new iPhone likely coming next month, we've seen price drops on the iPhone 4S coming from the likes of Sprint and Walmart, and now RadioShack is getting in on the action as well. Starting this Sunday, August 26th, RadioShack is dropping the price on all 4S models by $75 — and that includes the AT&T, Verizon, and Sprint models. This means you'll be able to pick up a 16GB model for $124.99, while the 32GB and 64GB will cost $224.99 and $324.99 respectively. The new price is available to both new and upgrading customers. The offer is in-store only, and RadioShack tells us that it will last "until further notice" — but we imagine that this price will stick at least until there's a new iPhone on sale.