When I was younger, my best friend + I woulf go to Vegas all the time and play blackjack. Sorta like the guy from the Hangover, with the World's Greatest Blackjack book (that's a good book btw). :-) Before we started getting all of our stuff comped at the nicer hotels, we didn't have a lot of money and we stayed at a bunch of places, and found that staying in the cheaper places on the Strip (at the time Excalibur and Tropicana) was usually not the best decision. The rooms/hallways smelled like smoke, it felt like there were fleas on the beds and generally gave a "busto" feel to the vacation. You're on vacation, so spend the extra few bucks a night and stay somewhere you're looking forward to going. Also, a lot of the nicer places have really low rates on the weekdays, so think about staying at a cheap place peak and nice place offpeak (preferably at the end of the vacation).
Also, I hear there are some condos on the strip. If you're going for a week, look into renting a condo.
www.vrbo.com. I'm guessing hotel rooms are cheap now, but with the real estate crash, a rental could be cheaper.