Seems to me you face two choices, given your question:
1/ buy low mileage for a premium and put very few extra miles on it so that it retains its value, or
2/ buy high mileage and get a bargain, then drive the wheels off it knowing that it didn't have much value to lose in the first place - once over 100k miles it will not be worth much or will be difficult to sell. If the engine explodes, covering everything in cheesy chocolate (!), well you had a contingency fund because you paid much less to buy the thing originally. Then call Hartech or similar. Or break for parts.
I'm very much option 1, but Phil997 (see above) speaks wise words I think.