People wanting to build their own home can get loans to cover most of the outlay as part of a new £210m scheme in what is claimed to be a world first.
Plots of land will come "oven ready" with planning permission in place.
Builders will be able to get a 75% loan for the plot and the full amount of the building cost with repayments only starting when the home is finished.
Self Build Wales is being financed by the Welsh Government and managed by the Development Bank of Wales.
The Welsh Government said it was the first scheme of its kind in the world on the basis it is offering a complete package of access to finance, land and planning permission.
The scheme aims to remove the barriers around self-builds and custom-builds - such as finding a plot, planning and finance, enabling more homes to be built.
Deputy Housing Minister Hannah Blythyn said the aim was to "unlock the potential" to build homes.
"While we are investing significantly in building new social and affordable homes, we also want to help far more people who want to build their own homes - doing so should not be the preserve of the most privileged households," she added.
About 10% of new homes in the UK are self-builds, lower than other countries around the world. Austria is the highest with 80%.
Figures have also suggested an average self-build house in the UK costs only 70-75% of its final value because no developer profits are involved.
People would have to live in their homes for at lease five years before being able to sell or rent it out.
Cenydd Rowlands, property director at the Development Bank of Wales, believes the move will help boost communities.
He added: "Bringing planning, design, construction and funding together will open the doors to self and custom build for people who would not otherwise have considered it as a realistic option."
Andrew Baddeley-Chappell, chief executive of the National Custom and Self-Build Association, said: "Self-building enables the delivery of more and better homes that more people aspire to live in and that communities are happier to see built.
"Homes that are more beautiful, more in keeping with their surroundings and more sustainable than the mainstream market delivers. Homes that can combine high technology with the work of local artisans."
Conservative housing spokesman David Melding said: "The devil, as always, is in the detail, but in broad terms, we Welsh Conservatives give these plans a cautious welcome.
"Home ownership is, after all, one of our most fundamental values."