I was listening to R. Grossman's lecture discussion and for some reason I started wondering: I've seen afar and also karka used as terms for real estate. Are they interchangeable or is there some reason this daf uses afar instead of karka?
Afar means "earth" or "soil" whilst karka means "land". In the mishnah he is marrying her on condition that he possesses a certain size of agricultural land - afar - on which one can grow produce. So afar does not mean real-estate (I assume that the latter phrase refers to houses or buildings) but rather workable land which is called afar because one plants in the earth. Karka is a more general term referring to land on which one could either erect buldings, or plant fields.
All the best