cheaply has 4 distinct synonyms spread across 3 of its 3 senses. Each sense below keeps its own list, because a synonym belongs to a meaning and not to a word: swapping one sense's substitute into another sense's sentence is how a thesaurus makes writing worse. Its one recorded opposite is expensively.
Counts are distinct word forms across every sense. A synonym that appears under three senses is counted once here and shown three times below, under each sense it belongs to.
in a cheap manner
“a cheaply dressed woman approached him in the bar”
with little expenditure of money
“I bought this car very cheaply”
Synonyms, antonyms and the broader and narrower relations for cheaply come from Princeton University’s WordNet. Full sources and licences.