Keep in mind FHFIF merch is all 10+ years old by this point - unless it's one of those massive franchises that's got millions of adaptations, the older a series is, the harder it is to find merch for it. I think IIRC, these were only sold online, right? so possibly they'd be rarer than stuff that was mass-produced and sold in physical shops *anyway*.
Your best bet is to add a "saved search" for Foster's and keep an eye out; something will probably turn up eventually.
