fill your boots
fill (one's) boots
To take or obtain as much of something as one can. Primarily heard in UK. Since that store announced its going-out-of-business sale, customers have been filling their boots with formerly overpriced housewares.
fill your bootsBRITISH, INFORMAL
If you fill your boots with something valuable, you get as much of it as you can. The fight has attracted a lot of people to the area, and traders have been filling their boots.
fill your bootstake full advantage of an opportunity to benefit yourself. British informal
2001 Sunday Herald By April 7, the Pitman factor will have reduced his price to about 12/1 so go on, fill your boots.