MEE 6 Pro in ear wired headphones for $44.99

Or the Shure SE215 Special Edition PRO Wired Earbuds

And here's a $12,73 1/8" (3.5mm), male to female, 25 foot headphone cable extension for your wired headphones, so you can move around freely.

If your in ear monitors come with a 1/4" (6.35mm) plug, you can get set of 2 1/4" to 1/8" headphone adapters LIKE THESE FOR $8.66

Wireless, Bluetooth in ear monitors are not recommended for live performing because of the latency (time lag) you'll experience between live sound and the earbud sound.