'Offer' in the Bible

What then is my reward? [Just this:] that, when I preach the gospel, I may offer the gospel without charge [to everyone], so as not to take advantage of my rights [as a preacher and apostle] in [preaching] the gospel.

On the contrary, the things which the Gentiles (pagans) sacrifice, they sacrifice to demons [in effect], and not to God; and I do not want you to become partners with demons [by eating at feasts in pagan temples].

Judge for yourselves; is it proper for a woman to offer prayer to God [publicly] with her head uncovered?