In Harvest Moon (SNES), you can upgrade your house. Talk to the man in the Workman's House in the forest. The first time you talk to him, you'll need to get in and out of the house to be able to order from him. It takes four days for each upgrade to finish.
Log Cabin[]
Wood Requirement: 0 Wood
Money: 0G
This is the house you start the game with. You can't get married or have a child until you upgrade your house, though.
Deluxe Log Cabin[]
Wood Requirement: 250 Wood
Money: 5000G
This upgrade is required in order to get married. You cannot have a child, though, until you upgrade one last time. Your house will be slightly larger when you obtain this upgrade.
Super Deluxe Log Cabin[]
Wood Requirement: 500 Wood
Money: 10000G
This upgrade is required in order to have a child. It is also the largest house you can get in the game.