Actually if you want more that three hours your best bet is
www.booking.com
You can find very nice real hotels - not hourlies - for anywhere as low as $400 per night at off peak times, and usually for $600-$700 is possible most of the time.
If you take an hourly, you have to pay that already, and still face the hassle of a fixed deadline when the phone rings and you scramble for the shower. Oh, and don't even THINK about extending at any kind of favourable rate, if you want to stay longer, you have to get dressed and go down to reception IMMEDIATELY and pay up front for another two hours (minimum) at the standard rate! Big time mood killer.
Much better to check in after lunch at a nice clean hotel, and you know you have the place until any time up to noon the next day ... who cares if you only used it for a lazy afternoon? ... and if it turns into a spontaneous overnight, or a quickie on the way to work, you got it covered