I don’t have any personal experience with this, but the El Cortez has a tax refund promo on their website.
https://elcortezhotelcasino.com/offers/paycheck-free-play-special/
And the American Casino Guide website has a bit more info about it.
https://www.americancasinoguide.com/vegas-values/ongoing-las-vegas-casino-promotions.html
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From: tomsk…@…com wrote: “Does anyone know of good check cashing promos in Vegas for IRS refund checks?”