Expect to find clean flushing toilets, soap, cold running water, and toilet tissue at public restrooms in the major tourist destinations and at tourist attractions (although the latter is sometimes missing even in nice establishments). At many markets, bus stations, and the like you may have to pay a couple of pesos for the privilege of using a toilet that lacks a seat, toilet paper (keep tissues with you at all times), and possibly even running water. Gas stations have public bathrooms -- some tidy and others not so tidy. You're better off popping into a restaurant, buying a little something, and using its restroom, which will probably be simple but clean and adequately equipped. Remember that unless otherwise indicated you should put your used toilet paper in the wastebasket next to the toilet; many plumbing systems in Mexico still can't handle accumulations of toilet paper.