Where are you three located? 

Investment Info:Townhouse fix & flip investment. 217 W 131st St, New York, NY 10027, is a historic townhouse located in the vibrant Harlem neighborhood of Manhattan.

I have posted my listing routinely to sites such as Facebook, Craigslist, Zillow and Land Search but still have not been able to find a buyer for the lot.

We also have a brick-and-mortar location in the DFW area.

The location all in,cost him X; he got an appraisal for the bank from CBRE national firmof XX and now the firm who called him mentioned paying XXX.

I did a search on my own  to help them find it and I can't find any insurance companies offering quotes for the Los Angeles area at the moment.

You can also find real estate investing groups through meetup.com, Facebook, or a Google search.

I've used the search feature on this forum but didn't have much luck.Are there any US investors, hard money lenders, or groups that invest in flips outside of the United States, specifically in Europe (Netherlands, Spain, etc.)?

There are at least two I found on a quick google search including Central Indiana Real Estate Investors Association (CIREIA) and INDIANA REAL ESTATE INVESTORS ASSOCIATION.

Quote from @Zachary Kay: Hey @Sarah Larbi,I recommend checking out Second Street (can google search "Second Street Costa Rica" and you should find their site).