The first four I picked up were a yellowish, soft plastic "no-glue" snap together models, two to a pack, from I believe a Smithsonian educational toy line. Huge size, a tricertops, tyranosaur, megaraptor and stegosaurus. I picked these up about two or three years ago at a Michael's craft store and I have never seen these models since then, but I always swore if I saw any more dino skelies, I would pick them up. I eventually painted these, and constructed a howdah for the triceratops big enough to fit four Medium minis. It makes for a good mini on the battlefield, and I've used them several times, from warbeasts in undead armies to obstacles in the gunfight at the Museum of Natural History.
A few weeks ago I stopped at a Big Lots and found bone colored, one-piece dino skeleton figs four to a pack for $3. Most of them were two quadrapeds and two bipeds, but one pack had a pterodactyl in it. These were smaller than the other models, made of yellowish plastic with a dirty brown wash that gives them a pretty good "dug up bone" look. These were closer to Large in size, with the triceratops being about two and a half to three inches from horns to tail, and the bipedal ones being a bit taller. They could pass for Large or Huge, depending on how you base them. Anyway, smelling blood in the water, I started hitting all my local Big Lots and found the same dinos in two-packs for a buck-fifty, which is when I pretty much cleaned them out. That brings my current total of skeletal dinosaurs up to 26 Large sized ones, and the four Huges I picked up years ago. The Huges were about $3.50 apiece ($7 a box for two), and the Larges were $.75 each.
The other thing I found at Big Lots were these plastic castle playsets for $5, for a line called Darkness Warriors. They have two figures that look like a generic Ram-Man and Skeletor and a small castle, but the great thing about these are the extras. A Large dragon, a Large skeletal dragon, a skeletal hand bursting through the ground, a plastic cage, a winged Imp creature, a pile of skulls and a bunch of weapons and standards. Most of it is made of a soft bendy plastic that I don't think would be paintable, but the level of detail on the cage and the dragons is otherwise surprisingly good.
As you can tell, I did a little post-Holiday splurging, but I regret nothing. All I need now is to come up with and then run a scenario that involves 30 skeletal dinosaurs. Should be fun.