There were three main classes of ceorl, although the dividing line between the classes was indistinct.  Second were the kotsetla, who paid no rent but had to perform numerous duties for their overlords.  The Thegn's Law source on the duty of a kotsetla:
"The kotsetla's duty depends on what is determined for the estate.  In some he must work for his lord each Monday throughout the year, or three days each week at harvest-time.  He need not pay ground rent.  He ought to have five acres; more if it be the custom on the estate; and if it is ever less, it will be too little, because his labour must always be available.  He is to pay his hearth-penny on Ascension Day, just as every freeman ought, and serve on his lord's estate, if he is ordered, by guarding the coast, and work at the king's deer-fence, and at similar things according to what his station is; and he is to pay his church dues at Martinmas."