Circus is the bottom of the barrel on the strip. Way too far at the other end of the strip but vegas on a budget had many people appealing to it.
I never eaten the buffet at circus vegas before. It has to do with distance. I'm not walking from my hotel, usually in the center of the strip to circus just for their buffet. If I need to drive and have a car, I'll go off strip so poor circus circus gets no love from me.
The cheapest is south strip at south point casino. The distance is probably why them prices are so low. Vegas on a budget a must have.

Breakfast
Mon - Fri: $16.95
Kid's Price 4-8: 50% Off
Kid's Price 3 & Under: Free
Mon - Fri: 7am to 10am
Lunch
Mon -Fri $19.95
Kids Pricing 4-8: 50% Off
Kids Pricing 3 & Under: Free
Mon - Fri: 11am to 3pm
Brunch
Prime Rib Brunch: $28.95
Sat & Sun: 8am to 3 pm
Dinner
Prime Rib Sat-Thur : $28.95
Seafood Night Fri: $49.95
Kids Pricing 4-8: 50% Off
Kids Pricing 3 & Under: Free
Sat -Thur: 4pm to 9pm
Fri: 4am to 10pm
https://vegasfoodandfun.com/south-point-buffet/