put the bottom rail on top

bet one's bottom dollar

To be absolutely sure of something; to be certain enough of something to wager everything.

bottom dollar

The last of one's money; all of one's money.

bottom fishing

Buying, or seeking opportunities to buy, investment securities or other valuable properties at a time when markets are depressed and prices are low.

bottom line

The summary or result; the most important information.

bottom of the line

The worst or lowest quality on the market, especially among a range of products.

bottom of the ninth

By extension, any last chance or final opportunity.

bottom out

Of a vehicle, to touch or drag along the ground or other surface.

bottom the house

To clean a house from top to bottom; to clean a house extremely thoroughly.