Don't really go for things beyond the games themselves normally, or at least what extras they might come with, provided I'm not paying above the base price. And even then, most of what I have I got pre-owned, usually reasonable or at least downright cheaply priced compared to average with a little patience, perseverance, and luck (location probably also matters, but every couple of months it seems like I find something worthwhile mismarked). And some of what I did get new has only gone up, one game from $50 or so up to $300 now, though I'm not inclined to scalp. As far as extras, OSTs and artbooks are what I usually have the most interes towards, though in a number of cases I can just find those scanned/ripped online, and often enough the western versions skimp compared to the versions Japan sees (fuck "sampler" tier soundtracks). And while I'm at it, fuck microfiber cloths and fucking stickers; is there actually a "scene" or whatever that is being catered to for those? Don't have any figures; they're neat, but I don't especially consider them worth the extra money myself unless they'd be properly pose-able, but there's also the factor that only one series I like actually gets them made these days, and most of the series I do like have since died. As far as stuff that would be nice to buy, there's some JP only art/worldbooks for a series I like that has seen a number of them over the years, but most of which don't have scans, and the ones that do are spotty in that they're either not high res, just image crops, or thoroughly incomplete. But as I don't even have access to a good scanner myself, and as a NEET it's a bit hard to make the sacrifice to unbind them for proper flatscans anyhow, so it's not like I've sprung for them. Also one book of particular interest is closing in on 18-19 years old at this point, and who knows what the average condition of copies of those being exported might be these days.
Most I've dropped on a game was $90 for Tales of Eternia PS1, but $60 of which was essentially a birthday present. Paid that much because it was complete and nigh mint, and as a friend and I were fans of the series, we could co-op the game. We both had a lot of fun with it, so I've got no regrets having bought it, but at the same time it's not a game I'd recommend people to actually buy given that sort of price. And in fact, $90 at the time was cheaper than average for a complete copy, and it's still creeping up as time goes on, so that's less reason to drop the money.