I'm a bargain hunter if there ever was one.... When I think of SPENDING $5000, I'm hoping to find a "$6000+ tractor" for 5 grand. And I also don't want a tractor under 40hp (pto....the only REAL way to rate hp)
So....following my criteria..........no 4wd's....Nothing "new"....Unless it's slap worn out....
Gotta go back in time a bit. IMHO, tractors from the 60's 70's and even early 80's are a better choice as an older used tractor than the newer (but still well used) models. Less "technology" to go wrong.....Plus, from my experience, tractors of ALL brands from mid 80's through late 90's had "quality issues" as the production shifted overseas. Once they got a handle on building tractors in the Orient, quality improved a bit. But in general, 80's and 90's weren't the "glory years" for imports. (There are a few exceptions, albeit rare)
For $5000, you can get a number of tractors that'll work an 8N into the ground....Not that N's were "bad tractors", they're not. Just a little under powered, out dated, and less than capable compared to many other possibilities. N's sell in the $1800 and under range around here. You get what you pay for....
So.....With your budget balanced against "what's out there"..... I'd suggest looking for the best example of a handful of these models.
My personal favorite(s) commonly found $5000 and under;
Massey Ferguson 35/50/65/135/150/165/240/245/250/255
Ford 3000/3600/4000/4600
John Deere 820/830/1020/1520/1530/2020 (Not many JD's under $5000 without going WAY back in time)
IH 444/454/574
I've owned just about all of those on my list at one point or another. Without question, the most reliable, best all around tractor I've ever been on (regardless of size/cost/year) has been my Massey Ferguson 150. The Perkins AD3-152 diesel is a frugal with fuel as any tractor I know of to this day. Good power, good balance, handy size, and rugged reliability, it's been the single best piece of equipment I've ever owned. They'll sell for under $4000 in average condition, and I've seen some mint 150's in the $5000 to $5500 range. At one point, I owned a Ford 3000 and an IH 454 at the same time as my MF150. The Massey would work circles around either and do it on less fuel. The 150 is everything good about a MF135 and a bunch more. After 40+ years of service, my 150 is STILL my "go to" tractor, even with 16 other tractors in my inventory. (13 of those are NEWER tractors too)
Of course, you could go with a much smaller tractor of newer age....Just NOT something I'd be interested in. BTDT...Got a little Kubota that I find just about useless.