The options for the best gaming mouse can definitely be expensive, but you don't have to drop a lot of money to get a quality mouse. For today only, HyperX's Pulsefire Core mouse has dropped to just $19.99 on Amazon. That's $10 off the original price, though the mouse has been sold for $24.99 recently (making this more like $5 off).
This is a budget gaming mouse with a Pixart 3327 optical sensor capable of up to 6,200 DPI. That's definitely lower than the 16,000 DPI offered by slightly-pricer mice, like the Logitech G305 or Razer Basilisk X, but you probably won't notice much of a difference unless you're a serious FPS player.
The rest of the feature list includes customizable RGB lighting, a symmetrical chassis design for ambidextrous use, and seven programmable buttons (including the two left/right buttons). Not bad at all for $20.
If the Pulsefire Core isn't quite what you're looking for, have a look at our recommendations for the best gaming mouse. We've tested all the greats to find the best mice options for your price range. We also have a separate roundup of the best wireless gaming mouse, if ditching the cord is a requirement.