looking for a custom search plugin or widget

Hi
I have just set up a WP site and looking to use it for a short term apartment rentals site. The theme I chose was not a real estate theme and I am now looking for a option to have a simple search feature for my site.

I have searched and searched and haven’t really found anything. can any one offer any help or advise on how I can have a search set up on my site?

Many thanks