There's no reason why the supermarket
should reduce their prices on the last day of shelf life. Caveat emptor in this case. Display until (or sell by) dates have no legal standing - just depends on how confident the shop is of selling the stuff by the use by date.
I lecture on food safety & I'm often surprised by the number of people who don't know what is meant by a use-by date or by a best before date and which is safe to eat (and legal to buy) after the date has expired. Best before dates are for products which are safe to eat past this date, but the quality of which may be reduced (e.g. tins, dried goods, biscuits etc). It is not illegal to sell food past its best before date. Use-by dates are found on 'high risk' foods on which food poisoning bacteria can potentially grow. It is unsafe to consume food past its use-by date, as bacteria may grow to unsafe levels after this time. It is also illegal to sell food past its use-by date. Almost all foods must have one or the other of these foods (there are a few exceptions). There is no requirement for a 'display until' or 'sell by' - these are for solely for the convenience of the shop.
Obviously, as Earthbabe comments, this relies on the packaging, chill chain etc being intact.
We do buy our meat from our local butcher, but it's definitely quite a lot more expensive than the supermarket.
Sorry

- I'll shut up now