I am not certain of whether you are looking to rent on an annual basis or for just one month. If you're looking for an annual rental, any Boca Raton real estate agent will be able to help you find a condo that fits within the rent range you have in mind.
However, if you are looking to rent for just one month, you may want to go to rent by owner websites, where you may find an owner who offers rentals for just a month at a time.
Also, There is one condo I have heard of that may cater to monthly rentals, and that is Laver's Delray Racquet Club in Delray Beach. It used to allow rentals up to 12 times per year.
You may want to search for that condo and locate an agent who has a rental listing in that subdivision.
Typically (though there may be a couple of exceptions) condos usually offer rental periods of 12 months or seasonal rentals of 4 - 6 months. As they get closer to December and don't have renters in place, the seasonal rentals may drop their demand to 90 days.
Marc Jablon, The Jablon Team
RE/MAX Complete Solutions