Some of the modular garden room companies have price configurators on their websites, like this one. They allow you to pick options for your building and see the effect of your choice on the overall project cost, immediately.
If you are looking for a building that is more customised to your needs, then bespoke design is the route to take. We are often asked if bespoke design is much more expensive than their modular counterparts. Bespoke designs do tend to be more expensive, but this is often because you end up incorporating more designer features!
We have researched the market and to get an idea of bespoke design prices. As a guide, companies will give you a price per square meter cost to work out your budget.