Who is a good saint to ask for intercession on buying a house? I know Saint Joseph is for selling a home, but I didn’t find anything on buying.
Any guesses?
I would think you’d go straight to Christ Himself.
Like 9:58
Jesus answered him, “Foxes have dens and birds of the sky have nests, but the Son of Man has nowhere to rest his head.”
Best wishes on the hunt for the home of your dreams.
I’ve always thought St Joseph, because he had to find housing in Bethlehem, and then in Egypt.
If he’s good enough for the Holy Family, he’s good enough for me! 
I would think so, too. 
I would still ask St. Joseph, or you could also pray to the whole Holy Family and ask for their help. You would be asking our Lord, His Blessed Mother, and St. Joseph, too.
St. Joseph for both the buying & selling of a house.
However, the notion that his statue should be buried upside down in the ground to help the sale is superstition and is a sin of grave matter.