Don't forget to have the current owner check the water parameters currently in in the tank. When I bought a used tank (fish included) the guy admitted he hadn't cleaned it in approx 3-4 months.
We lived only 30 min away, but x4 home depot 5 gallon buckets and a stressful drive later... one of the cichlids ended up dying from what I would guess was ammonia poisoning.
I was trying to get their tank setup as fast as possible...it was really chaotic. Especially because some fish were jumpers. :S
If I could do it over again, I would have brought some aquarium ready water to mix in with their current water, more buckets, & ammonia lock.
Good luck to you!! I wish you the best!