Hi, I am not a broker or real estate agent. I can tell you about my experience building with one of the turn key or package builders where you choose options or upgrades after deciding on a plan and selecting a lot. With the builder we went with, they had lots to choose from in a specific subdivision. You had base house + lot + upgrades and then an agreed upon price. From the perspective of unexpected price increases, non existed since they were all negotiated before they began any construction. That is a huge piece of mind! It was surprising, as first time home owners, how much the addition of concrete and landscaping costs. In most subdivisions, you are on a specific time frame to get that done (ie you have to assume that cost as well within 2 years of home ownership at a minimum). Here's an example of the costs we paid over 10 years ago when we built: 7000 for concrete (double driveway and fairly large patio in the . back, no walk ways; and roughly the same in landscaping.) For the landscaping, we had a professional draw out the plan and ordered the less common plants from them and did the rest ourselves....a back breaking experience I would never repeat.
Overall, we were very happy to have gone the route of building a home. The thing to consider these days is that there are so many homes on the market that really have a lot of value and are most likely in established neighborhoods etc. with mature trees/landscaping complete. You need to ask yourself if you can find that on the market today for less money than building new. That was not an option at the time we built. (not many houses of the style we wanted in the area).
Bottom line - call the builder you are interested in and ask how much the lots are for the house plan that you are thinking of building. If you don't know which plan, use parameters like: 4 bedrooms with around 2400 sq ft and they can give you a range of prices for the lots they know of.