When it comes to older XR value, condition and goodies are my most important measurement. Xrs are pretty reliable, so used ones tend to be safe buys. You can check the cost of adding goodies, which adds up fast. The tri-clamp and pro-tapers are worthy upgrades, as well as hand guards. Check the under-side of the bike for rock damage. Start it up to see if it smokes. Hard to determine mileage on XRs (no cumulative odo), so the condition is what counts. If it's in good condition and it has desireable (for you) upgrades, I think it's a good deal. However, if you plan to do a lot of trail riding/dual sporting, I've seen prices on XR4s with baja kits for not much more.