My first chainsaw, that I actually owned, is a Stihl 011 AVT given to me by a neighbor. At the time I knew nothing about repairs, and twice paid to have it repaired. Despite it being free, I'm into it for at least $100.00 more than what I could sell it for.
I have an Echo CS-440 sitting in the garage, that bought for $40.00 knowing it would need at least a piston. Once I starting checking it out I found out it needs at minimum a P&C, and a brake band. I soon found out used Echo P&Cs are nearly impossible to find around here, and the cost of a new top end is just about what I might get selling it (and that doesn't include the cost of the brake band). The CS-440 is still in pieces in a box in my garage.