You car is not a very good asset from the bank point of view, so it's not going to be cheap. But the typical example is to draw on your mortgage, (equity release, i.e. reborrow a little more against your home). That's pretty much as cheaply as a consumer can get liquidity against an illiquid asset (home).

And that's pretty much what banks do with the Fed. They have assets that they get funding for from the Fed with a short term repo transaction. In theory the Fed takes very little risk on the transaction.