Was there once on a Saturday. It's an R. G. Canning Show which means a hefty admission price. Mostly shoes and guavas, found no casino related items. Oh, and some shoes with guavas stuck to them. Maybe you will have better luck, never tried it on a Wednesday - didn't know it was open that day.

For anyone interested, exit I-10 in Banning and take the old highway (99 once), swap meet as I recall is on the easterly side of town. Park on the small street leading to the swap if you can find a space - as I recall there is also a parking fee to use the lot.