means I'm around, or depending on the context that I'm supporting you. "Ei Thomas, vou estar por ai na Philadelphia, vamos fazer algo juntos?" "Thomas, sei que está passando por momentos difíceis, se precisar estou por aí."

Thomas if you want a language partner to practice Portuguese, I would be glad in help you. I am Brazilian and I love English, but I have nobody to talk. So let's team up to help each other.

"Eu tô por aí" = I'm wandering in the world (you are walking anywhere even you don't know where)

'tô por aí' means that you're in around; Usually in songs, this expression means that the person is around and if someone want to find him/her it won't be hard.

what have you been doing? nothing special, I am thereabouts (estou por aí), here and there, but if you need something I'll be around (estou por aí)