I use 2 variants of the above for my bulkier stuff or for fragile single minis :
- any rigid box (shoe box, big tupperware, biscuit tin ) with aquarium filtering medium - it's a synthetic wool that can be bought for cheap online, makes it easier to fill gaps with it than bubble wrap, but can be a bit annoying to remove some loose strands when you take our the minis. It's light and allows the ox to be tilted any way during transport, I use that on planes.
- any plastic box and blue tac /any other brand of similar adhesive paste/putty that is removable. Put it under the base, stick the model to the bottom of the box or on the lid and close. Better to transport this in a set position, as if it's not upright it may ease the model off its pasty support after a time.
A friend uses thin adhesive velcro strips under the bases and a velcro lining in a case.