I've been thinking about this question since last winter, but I was too busy to do much about it. So I had to buy some more bags last week, and throw 'em in the back of the truck. I've used sandbags for years, but I think I'm going to get one of those water bladder things. Have any of y'all tried those?
One problem with tube-sand is that exposure to the elements seems to really weaken those bags, and they start spilling sand everywhere. Eventually, they have be replaced, and I'm left with a bunch of sand. I thought about building a box to put the bags inside, or a set of small boxes - one bag per box. I guess that might be cheaper than a water bladder, but not by much. And the individual boxes would make the heavy sandbags even heavier for me to move.
The other 2 problems are having to store the sand in the off-season, and just the fact they're such a pain to move around.
I used to have a great solution to all those problems. When I worked for the mall, I kept the bags on a wooden pallet that fit neatly between the wheel wells of my Tacoma. In the spring, I'd lift it out with the forklift at work, and put it somewhere in the cavernous, indoor loading dock area. Being shielded from the sun for most of the year, and laying flat at all times, the bags lasted for years. Once I had them on the pallet, they were easy to move. Just drop the pallet back in my truck, come autumn.
But that is no longer my situation.