Nvidia's G-Sync and AMD's FreeSync technologies are more down-to-earth. They help increase the quality of the gaming experience and smooth out frame rates by letting the laptop screen refresh at a variable rate that depends on the output of the GPU. Look for support for one of those technologies if you're a stickler for perfectly rendered visuals. They tend to be in pricier machines, though, and G-Sync is far more common.
When choosing a gaming mouse, you have a wide range of options to consider. For starters, do you want a wired or wireless connection to your PC? There are good wireless gaming mice available, including some with dual wireless/wired connectivity, but many serious gamers tend to prefer a wired connection for fear of a lag in response time or too short battery life. You will need to decide between optical or laser sensors for precision tracking, and whether or not you want an ergonomic design.
Dell Home, via its Member Purchase Program, offers its Dell 15.6" Laptop Gaming Backpack in Black/Red for $28.49 with free shipping. That's tied with our expired mention from four days ago as the lowest price we've seen for this bag. (It's the best deal we could find now by $20.) It accommodates laptops with up to 15.6" screens and features a shock-absorbent EVA molded front shield, adjustable shoulder straps, and a deployable rain cover.