Building duplex with in/around Portland metro

[Belay Tarekegn]

Hi all, Me and a friend of mind have been looking for buying our first home around Portland (NW and SW), but because of the low inventory and ever increasing house price its been tough to find the house that we liked. And we have been thinking if it is a good idea to build a duplex on open lot(we seen some lots in good neighborhood for around ~180k) instead of buying a house that we don't like for ~400k. I seen builders like Pahlisch build duplexes but i don't know what their price is.  https://www.pahlischhomes.com/pahlisch-select/  

I know its expensive to build a custom house, but I want to know it it is expensive to build a duplex and split the cost( for example  cost of building a duplex with max 2000sqft each).  I just want to know what are your thoughts and if any one have this same experience will be glad to know more.