I see people trade in their dirty used car because something like a radiator started leaking and they are worried that other things will start failing. the trade in will be valued at 4k - 6k and they will put in another 4k and start 5 years of payments and higher insurance. It is a VERY common logic that is mathematically fallacious. That logic though has allowed me to buy all of my vehicles because i have Never and have no plans to ever buy new.
to love an 80 means you will need to enjoy the fix up process, which can only happen stress free when you have another vehicle to run and get parts for it. \
Working on your only transportation, Whatever it is, is stressful and you never get to do the job on it you really wanted to. I recently bought a tundra, sounded like a choir of crickets and had a bad vibration. The previous owner got a new chevy and introduced higher payments but, as he said it, he has a warrantee. as i understand the current production at chevy... he'll be using it. I got the tundra, put new headlights in, ripped out all the trainhorn crap and other stuff as well as spent a weekend doing new timing belt, seals, all those bearings up front, including alternator, and fixed the driveshaft. Not expensive but i have an 80 i can drive to go get parts etc. Now it runs great, very quiet and smooth. I've removed likely all the reasons the guy didn't want it anymore.
I got it so i can go back to relaxing and working on my 80 and my 79 pickup on my time without rushing.
My logic is this. don't go in to debt unless it is necessary, and get a vehicle that fits your lifestyle and aspirations. My life requires a pickup and an 80 right now. Figure out what your life requires for transportation, and buy something without going in to debt. If you have the money, two used vehicles is better than one new one.
to the OP.. xterras are cheap for a reason. they are often listed around here in need of transmission or engine just won't start and stay running. There are plenty that seem to have steering rack issues too. Of that is what you want, go for it but know what might be coming and do the work to make it reliable.
what people are telling you, is that any older vehicle, even a 4runner etc, is going to need some freshening up, and if it doesn't then it has already been done and will be priced accordingly (hopefully they are honest).
last comment... buy an 80, you only live once, and when/if it doesn't work out, make someone on here a great deal on it for whom it might workout.