Cockroaches: A deal-breaker?

[Noelle Lothamer]

I have an opportunity to buy a performing 3-unit (with 2 additional potential basement units) via private sale from an older landlord who is looking to start stepping back from his responsibilities. He owns around a dozen properties, so if things went well, there could be the potential for more private deals down the road. Most comparable properties in the same neighborhood are listing around 120-150k; I think I could get this one for 90k. BUT-- my friend is a tenant there and she reports that the house has cockroaches! 

This is a free-standing house, not attached. Also, I lived in this neighborhood (albeit several years ago) and never had a problem in my house or saw them in friends' houses. If the current owner has it professionally sprayed, what are the odds of me having to regularly treat this? I don't want to buy a property and have to spend thousands per year on pest control!! Never had to deal with this particular situation so any advice is appreciated.