Here's an interesting article from Coldwell Banker's US website on the process of buying building a custom home:

If you want a new home, but aren't interested in a cookie cutter subdivision, consider building your own custom home.

It's a "toss up" whether building your own home will be cheaper than buying one in a subdivision, said David Lupberger, a home improvement expert with ServiceMagic.com. A custom built home could run $100 per square foot, excluding land costs, he said, but up to as much as $300 per square foot with high-end finishes (excluding the cost of land).

Follow up:

And don't discount the amount of work and time a custom built home will take. The design process can take three to nine months plus another four to six for construction.

"You have to understand there will be 500 different selections you will make," Lupberger said. "I've seen people who loved it and people who are just overwhelmed."

The upside? You get a unique home that has your own personal stamp on it.

To get started, purchase a piece of land. A site in a pre-existing development is usually prepped for the installation of electricity, phone, cable, water and sewage. If you already know what type of home you want, check the zoning and building code restrictions to ensure you can build it before you buy the land. Check for utility easements and setback requirements.

Then, create house plans by hiring an architect or a design/build firm, which offer architectural and construction services. You can also buy generic home plans. Many web sites like edselbreland.com, stockhouseplans.com and houseplandesignworks.com offer these, which can run from $600 to $3,000 and up depending on the package. You can narrow your choices by square footage, floors, number of bedrooms and bathrooms and other features.

These are difficult to customize, but some Web sites allow you to make changes for an additional charge. You may want to hire an architect to make changes to the original design for a minimal charge and to make sure the design meets local building codes. This should cost thousands of dollars less than working with an architect from scratch.

Read the entire article at Coldwell Banker.com