Hello,
Three Bedroom Suites are pretty rare in Las Vegas, as most are either held over for high rollers or if they are released to the general public, are several thousand per night.
I your best bet, and cheapest if you want 3 bedrooms, and want to be on The Strip, would be Elara. Their 3 Bedroom option, which has 3 king beds looks to be around $1,100 plus tax and fees. This suite is awesome as it has a full kitchen and a drop down projector TV in the living room.
Going up in price it is possible to occasionally snag a Cosmopoltian 3 Bedroom West End Penthouse for $1,500 a night, though weekends will be more expensive. These come with butler service and some with balconies.
You might want to consider doing one, 1 Bedroom suite as a hangout spot and 2 regular rooms with 2 queen beds as it will allow for many more options and will also come out much cheaper. You would also get more beds, though you didn’t mention if it was 3 couples or just 6 friends who would be okay sharing beds or sleeping on roll aways or couches.
Let me know if you have any further questions.
Thanks!