Appraisers are using MLS data and often it is lower than actual rents. 

Reliability of Regrid Zoning InformationIs the zoning data provided by Regrid accurate and up-to-date for development planning?

The data @Devin Conley posted is pretty solid from my experience (I do not know Devin nor how he sourced the data, just going by my own investing experience).  

Lots of data there.

NAR Says - Existing home sales fall to lowest level in nearly 30 years and Median housing prices rose to a record high"The National Association of Realtors released data that showed existing home sales declined to the lowest level since 1995 last year, with 4.06 million homes sold on an annual basis.Meanwhile, the median home price median home price rose to a record high of $407,500 in 2024."

Then take that data and skip trace it for numbers email etc.

Just ensure the cost data sources are very clearly documented.

They typically will have data and newsletters as well they can send you.

That being said, all of these lead-generating companies do the same thing and often use the same data to source contact information.

Use tools like AirDNA or Mashvisor to provide market data on projected rental income and occupancy rates, and make sure your lender works with appraisers familiar with short-term rentals.