Generally speaking, Twin Comanche.
As to cost, it very much depends on the original condition when purchased, and just how much 'catch-up' maintenance you must accomplish.
If we look at other airplanes, some can also be quite economic.
My 411A, for example.
On the other hand, I fixed nearly everythoing just after purchase, so it has been reasonably trouble-free since then (twelve years ago).
Pays your money, takes your chances.
