Licenses are not required for many businesses. If you are wondering if the business is registered with the state as a corporation, partnership, LLC, has filed a ficticious firm name, etc., you can look up the business at
Incorporate or Form an LLC in Florida, File a Fictitious Name, File your Annual Report. This may help you feel more comfortable if you want to make sure the business is "viable". You can also ask to see evidence of worker's compensation insurance and liability insurance.