How low should I offer on this house?

[Jeremy Skeen]

So I'm looking into buying my first house as part of a brrrr strategy. The house I'm looking at has been on the market for just short of a year. It is absolutely hideous but seems to have good bones. The average house in the same neighborhood (that doesn't need a ton of work) is valued between 80-120k. This house is listed at 50k. It needs quite a bit of work, but I am capable of doing most of it myself to save money. It would probably take a few months to be rent-able, but carrying costs would be negligible.

I really feel this house would be a great start for me if I can get it cheap enough. At the same time I feel confident I can make money even at its current price. The real question is how low to shoot without making them mad? It's been for sale and vacant for so long I feel they have to be ready to unload it.