Take a look at this thread. Most seem to get 'em from Cosco, some from Walmart. I saw some today at Party City. Prices seem to range from around $30 to $50. If you go to a specialty store like Spirit, you're likely going to pay double.
Since they are "specialty" holiday items, they're going to be pricey,
especially if you want a decently-made high-quality one. You might be
lucky to find one on sale, but the closer it gets to Halloween, they'll
be even harder to find. This is just my opinion of course - good luck though!
The only other thing I'd mention is there seems to be two main different types - the "pose and stay" and the ones with loose joints. The pose and stay are handy because you can stand or pose them with very little effort. But if you're looking for a specific pose you may find the motion too restrictive. So just keep in mind what you want to do with them. The "pose and stay" types are newer, maybe just the last couple years. The other ones might be a bit cheaper.
I just got a pose n stay at Target for $40, saw the same in CVS for $50, Bluckies (those blow mold skellys you see in Big Lots) are really overpriced now & not even close to being anatomically correct but they're still around & can be fun to use &/or modify.
have a couple of decent knives,
good running shoes.
Honestly, when it comes to life-size and realistic in detail and/or proportion, you get what you pay for.
For years the standard supplier for the high-end stuff was the 4th class materials from Anatomical chart company. The 4th class stuff is miles better than department store props.
I just ordered a 5' pose & stay online from CVS - I had a 30% coupon and because I let it sit in my 'shopping cart' for a couple days, they sent me an email for another $5 off. So with shipping I paid like $36 for it. That's just the one from this year. I got 2 from Walgreens on Nov 1 last year. Menards, Garden Ridge, etc. But yes - $30 - $50 is the norm.