Let’s look at some Idioms for ‘buy’
That y buy something ‘for a song’ means you buy it very cheaply.
For instance: ‘I got it for a song, I can’t believe how cheap it was.’
To buy something ‘sight unseen’ is to buy it without seeing it.
‘I bought the iPhone sight unseen, so I had no idea there were scratches on the screen.’
To ‘buy time’ means to do something to extend the period of time before you have to do something.
‘A small loan from my mum helped me buy some time, but I knew I would have to get a job.’