Buy or build?

i'm in need of a much larger home. i have a 10 acre property at my disposal and am looking at the possibility of buying a manufactured or modular home. still have not ruled out buying an existing house. my main concern is cost. i found a floorplan for a manufactured home i liked for $96,000. how much more is something like this likely to cost? i have ideas about septic, slab and well costs. what all else could be coming up? the house price includes heating and cooling systems. also are these structures worth buying?