In reply to JonLongshanks:
There are a few things to consider.
You can either try and keep the sand out - and that's going to be hot, sweaty and probably unsuccessful. The military solution is to fix your trousers around the top of your boots. If you're out to enjoy yourself, then everything loose is the way to go.
Or, you can accept that sand's going to get in, in which case some room is good. Air helps keep your feet dry and gives the sand some space to go (i.e. around the edges). A leather liner or single layer (suede outside, leather in) is much better than fabric which will both wear out and hang onto sand. Small sand is no problem, but a big piece of grit you're going to have to tip out, so easy lacing is good. I found the slightly higher, suede loop ones the best, both in terms of comfort, ease of lacing etc and generally keeping stuff out while letting feet breathe.
As far as support - no issues - they're low, which helps with stability, and a bit of rock to walk on is a relief from schlepping though sand. Just as long as they've got a decent heel cup so that your foot doesn't slide sideways off the sole. Don't worry about tread patterns - anything will do. There are lots of variations in materials at this price point, and fit can be a bit variable too, but they're a sound option for walking (but not crawling around on your belly or kicking in doors with a massive bergan on your back...)