'Expense' in the Bible

Have we not the right to our food and drink [at the expense of the churches]?

[Consider this:] Who at any time serves as a soldier at his own expense? Who plants a vineyard and does not eat its fruit? Or who tends a flock and does not use the milk of the flock?

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.