Sure, you might already have some speakers, but do you have a giant speaker with lighting effects that can create noise complaints from neighbors? If not, you can get a refurbished JBL PartyBox 300 for $287.99 today only from Amazon-owned Woot, which is $212 off the current Amazon price for a new model.
This is technically a portable speaker, as it has a built-in rechargeable battery, but the height of 27 inches and 35-pound weight means you probably won't be sliding it into your bag very often. Still, the PartyBox has two 6.5" woofers, three 2.5" tweeters, a battery life of up to five hours, and fun lighting effects. You can play music on it from Bluetooth, RCA ports, or the 3.5mm aux connector. There's also a microphone/guitar input with an independent volume control.
The speaker is on sale for today only from Woot, and Amazon Prime owners get free shipping. The speaker is refurbished by JBL itself, and comes with a 1-year warranty.