buy up

verb

Etymology: From buy + up.

To buy the whole of; to purchase the entire stock of something.
“The marshland was bought up by a housing company.”
“And when Zootopia needs to expand, rich landowners like the feline Milton Lynxley (David Strathairn) are more than happy to buy up these neighborhoods, displace the animals that live there, and erase their history in the process.”
To buy whatever is available of something.
“According to this saga of intellectual-property misanthropy, these creatures [patent trolls] roam the business world, buying up patents and then using them to demand extravagant payouts from companies they accuse of infringing them. Often, their victims pay up rather than face the costs of a legal battle.”
To buy off; to pay in blackmail money or similar.
“Sir Leicester Dedlock, Baronet, it's for you to consider whether or not to buy this up. I should recommend, on the whole, it's being bought up myself; and I think it may be bought pretty cheap.”