We are creating an analytical tool for real estate in USA and have a problem getting a ballpark estimate on data costs, as companies like CoreLogic who has this type of Data are not answering on how much this type of data would cost. Maybe someone knows a ballpark estimate on how much would it cost to get a bundled transactions data of residential real estate (sale date, sale price, pictures of sold properties) mainly we are interested in California, but the whole USA data would also be of interest. The same question would also apply for Canadian market, as governmental institutions who hold this data are extremely slow in giving their answers.
In my experience, this data has been at no cost. Most property appraiser sites offer sales data as an excel file for download. Each property can be looked at with exterior photos, or base floor plans.
It would take quite alot of dara entry to input into a program, the issue would be the accuracy, if properties change hands within a year.
Hope this helps!