This is the 1693rd most frequent Japanese word.
食える
"食える" means "to be able to eat" or "to be edible."
The word '食える' is used here to mean 'can afford to eat' considering financial constraints.
彼は毎日コンビニの弁当しか食えない。
He can only afford to eat convenience store bento every day.
'食える' in this context expresses the speaker's capability or stomach capacity to eat.
この店の特製寿司は何皿でも食える。
I can eat as many plates of the special sushi from this shop as I want.
In this sentence, '食える' is used to mean 'something that can be eaten or is edible'.