If you have a financial ceiling of $20K, then you should be able to find a well maintained one with good accessories.
Stop at 1998, otherwise you'll be buying an early TD5. Even if you have 5 cars checked out at $200ea for an inspection, that's still cheaper than buying the wrong car and replacing a gearbox.
I had a budget of about $10K 4 years ago, and I found a 1997 110 Station Wagon with 112,000km, Warn Winch, ARB Lockers, Cargo Barrier, Wheel Carrier, Long Range Tank, Suspension Lift, UHF, IPF Spotties..... for $18K. I stretched my budget and bought it. The extra $8K I had to find meant I saved years to researching, saving, bargaining and fitting accessories. It had some minor dents, as would be expected of a doubled diff locked Defender with winch but no rust or structural damage.
The trick is not to be in a hurry and to search every day on carsales, tradingpost, ebay etc. Mine was advertised in the trading post, but I noticed the advert as it went on line before it got to print, and got in early with my deposit.
In the four years I've had it, I've had to replace a fuel lift pump ($65 shortly after buying), uni joints, rear shocks & tyres (wear & tear items). And I replaced the clutch & Timing belt at 165K km, as well as had the A/C regassed. It's now done 200K and I've got a new set of injectors for it. I maight go out and fit them now, now that I've reminded myself of that.
Since I bought it, a couple of mates have also gone and bought 3ooTdi Defenders and are also very pleased with them.
There's not a lot to go wrong, so start with something structually sound and maintain it.
