Oil prices affect styrene prices.

A few years back when oil exploded, a lot of model companies raised prices considerably. I haven't bought Tamiya static kits for some time since other companies like DML have been offering more choices, so I don't know if they raised them then, but as Karel47 mentioned, the FO 1/16 kits haven't gone up at all. I know about 10 years ago I got my Tiger I for just under $600 and that was after months of searching (and stumbling across an amazing deal) and the M4 was well over $500 IIRC.