As far as major Strip casinos are concerned, our call-around confirmed that table minimums are pretty standard and you certainly won't find the kind of limits you're looking for at the Mirage (crap/roulette minimum: $10), Mandalay Bay ($5 day/$10 night), or the Wynn ($25).
However, our survey revealed that, if you're prepared to travel to some of the smaller out-of-the-way joints, you can still find what you're looking for, with $1 craps and 50¢ (or less) roulette available at a number of venues, some of which are definitely more than a cut above your average dive (check out Happy Hour at the Westin Casuarina, for example). Click here for our full table of findings, but be aware that the figures listed represent the absolute lowest limits that these casinos ever offer, and that during busy periods (evenings, weekends, when big conventions are in town) you may well find that these limits are raised, so call ahead to check before you make a special trip.