Chessex makes several different figure cases. Though none are really suitable for very large figures.
Many gamers I know use pistol cases to carry miniatures. I believe you can find very inexpensive ones and they are good for larger minis because there are no cutouts - just the eggshell type foam.
For very large figs I have a cardboard box with foam I cut out specifically for them. It does not look pretty but it works.
Yes, you can get flexible plastic tackle boxes at Walmart, then go to a craft store and get some sheets of black foam for a couple of dollars, and some form of adhesive, cut out the foam and glue it to the bottom of the tackle box partitions, and there you go, cheap as can be, and they come in different sizes too!
Just go to Walmart and buy some Pistol cases. I picked up several for $10 each. $10 bucks each for a huge 2 level pistol case! 3 layers of foam in each case, so you just cut your dragon sized slot in the middle layer and you're done.
They do have a big bald eagle on the side, but I can live with that for $10.
The foam sheets have little squares already cut in them. You can configure each foam layer to fit the miniatures you have. Besides several layers for normal 30mm figures, there are two double thick layers. I have my Ral Partha Stone Giants and the more recent WotC Hill Giant in those layers... standing upright with room to spare.
For my miniatures, I highly recommend the Camelot Cases found on the Excelsior Entertainment site. In the larger cases I can get either a lot of figures in them or my assembled big dragons. I have found that if I cut the foam layers to the desired depths I can get both the dragon and other smaller figures in the same case.
I have had these cases dropped and backed into with a car and my minis survived unscathed. For the price, they are well worth a look.