Google Translate and BabelFish.com both provide free translations of Spanish phrases such as "buscar a una persona." In addition, Freelang.net provides a list of volunteers willing to translate short Spanish phrases for free. As of March 2015, the website listed nine Spanish-English translators.
The Collins website and Dictionary.com also have free Spanish-English dictionaries. The websites do not translate entire phrases, but they allow users to translate one word at a time. In addition, they have audio files with the pronunciation of each word.
"Buscar a una persona" means "to look for a person." Buscar is an infinitive verb meaning "to look for" or "to search." "Una persona" means "a person." In Spanish grammar, speakers add the preposition "a" before any direct object that refers to a human.