Once I win a repossessed vehicle, am I allowed to drive it off the lot?

It depends entirely on the vehicle's title status and condition, not on the fact that it was repossessed. A repo with a clean title that runs and drives can typically be driven away once payment, paperwork, and any required temporary registration are sorted. A repo with a salvage title cannot legally be driven on public roads until it's repaired and re-titled in your state — it has to be transported. Always check the title status field on the listing first.