Driving to
Las Vegas from
Anaheim will probably take you close to 4 hours...more or less depending on what knid of top speed you wanna hit en route. As far as bussing goes, if you stick with one bus company (make a round-trip ticket, for example), most will only have one trip back and forth each day, since for a bus it's like a 4.5 hour trip. So for example, you'd take a bus in the AM from Anaheim, get to LV in the early afternoon...and a couple hours later a bus (perhaps the same one) would leave to go back to Anaheim. So you'd probably want to make a trip out of it and stay a day or two at least.
Accommodations for
Las Vegas hotels vary greatly. Chances are there's something for you no matter what your priceline, but the cheaper ones will probably be further from the strip and/or further from your bus drop off point.