These committed saints not only offered their time to Apollos but their hospitality as well. I doubt this was a one-time event. It probably wasn't fellowship over a pizza after church. It is quite plausible that he may have lived with Aquila and Priscilla for a while. Ministry is not just for the church sanctuary.
Much empowerment takes place in the home.
This thought tells us much about Apollos' attitude. He, an extremely intelligent, well-educated Alexandrian preacher was willing to learn at the dinner table of a couple of tentmakers. Being empowered by others begins with humility. We know from other biblical passages that he later became one of the pastors of the church in Corinth in that region. Because of the empowerment of Aquila and Priscilla, the whole church got behind Apollos and urged him to use his spiritual gifts in further ministry.