Generally when I see an entire line being clearanced at a retailer or, even worse, show up at an overstock retailer (TJ Maxx, Marshall's), I assume that news of an outright cancellation can't be far behind. The latest potential victims might be my much liked S.L.U.G. Zombies (currently on clearance at some Targets) and the Transformers Bot Shots line (currently showing up at some overstockers).
Given that Jakks Pacific's S.L.U.G. Zombies line is something of a fringe item, it's somewhat worrying news. S.L.U.G. Zombies is a reasonably priced line that appeals to some older (mostly nostalgic) audiences and, presumably, also some younger ones but I can't imagine it's terribly well-known. So far they've released four regular series (with the last one just now hitting retail) as well as some holiday packs. It would be heart-breaking to see the line die off so soon.
Transformers Bot Shots is something of a different matter, being a spin-off of a very well-established property that commands prime shelf space. At US$4 for a single-carded figure (and US$8~10 for a 3-pack), the Bot Shots are also very reasonably priced and affordable. Given the franchise name and game component, I would be extremely surprised to see the line fail. That said, the whole game component might have made a splash over twenty years ago (when such things were more common) but I can understand if it failed to gain traction with a generation growing up on video games.
At any rate, snap up the bargains when you can and pray that this isn't the end.