I'd say, for what it represents and the actual cost, it's...rather cheap. I can't say if it's a smart purchase or not, but it's actually cheaper than most replica weapons you see on other places.

This may be a problem, since in terms of replica swords, cheap tends to mean bad quality. There's already a problem with stainless steel (most of the time, the used metal is 420/440 stainless steel, which is rust-resistant and of good quality but often forged very badly). Normally, for a fully-functional sword, you'd be looking for hogh-carbon steel, Austensite or Martensite, which are the best quality steels you can find around (and basically, both Austensite and Martensite are essentially created through cold iron techniques, if my memory doesn't fail me); IIRC, a properly forged Japanese steel katana's blade is made of Austensite on one of the sides (though you can disregard me on that one).Usually, 440 stainless steel means that it's factory made and meant to be used for replicas; while it isn't bad to show (I have a tsuba-less katana and a hand-and-a-half sword forged from 440 stainless steel), it isn't practical (then again, a weapon of that size isn't very practical either). It doesn't say if it's hand forged (which I think not), or machine-made (which is usually a very bad sign), so I'd take that with some concern.

Full tang is a good sign; while it's not meant to be used, it is meant to allow a solid grip. I'm worried about the proportion of the tang relative to the blade (I presume the tang must reach the end of the hilt and be properly forged to withstand the width of the blade, or else the tang will break right at the point where the guard and the handle meet).

Size and weight-wise it is, oddly, appropriately large and heavy for a weapon of that size. Don't be scared by the 14 lbs. of weight: it actually is proportionate to a weapon of the size. Compare to a replica of an English Two-Hand Sword; the aforementioned blade is actually bigger in length than the Buster Sword, yet it's full weight is at most quite a bit over 4 lbs. The width of the Buster Sword is roughly 3.4 times the width of the pointed sword, and it has roughly 3.5 times the weight; that is reasonable since it's blade is shorter, the width is larger, and the thickness may probably be larger than the English Two-Hand Sword, so the proportions should check; if anything, the Buster Sword may be a tad lighter than a weapon of lesser width but equal length and thickness, considering general proportions. Of course, the problem is the blade's balance; if anything, the combination of the blade's width and weight should make it hard to lift. That's to be expected, though.

In conclusion: since it's 440, it's actually pretty cheap if only for exposition. High Carbon Steel would be practical but expensive, and actually most weapons made with 440 Stainless Steel are pretty expensive as well. Given that it holds pretty good proportions to a functional blade (the tang, the weight/width proportions and the material doesn't make it fully functional tho), it's actually a pretty good buy. So I'd say that, if you want it, go for it; it's not going to be a bad buy if the intention is to show it off. It also requires little maintenance, perhaps one or two wipes for the occasional dirt. It may be detail-accurate but it's not exactly size-accurate (I'd need to find the actual size, but based on the Final Fantasy Wiki, it's roughly smaller: 4'3" instead of 5' as the Wiki states), but it's not particularly practical (but, as mentioned several times, you don't want it to be actually practical)

Now...if what Jin says is true (looks like sheet metal, which means it has little thickness), then it's a bad buy. I'd think of the thickness, since what Jin says is true to a point: a toddler can't bend it, and perhaps no one may be able to lift it so that it can bend properly, but place it on your head and try to bend it, and if it's that thin (and badly forged/not forged at all), it will be like a wire: it'll stay bent.