You may be able to buy a side of beef from a butcher, a farmer or an abbatoir. While it is a large purchase, a side of beef lets you plan what you will eat in the long term instead of making food choices based on supermarket pricing.
A butcher can cut the side of beef in different ways, depending on the cuts you want to eat the most. They charge by the pound for the meat, so you can compare the butcher's price with the supermarket's price.
You may need to plan in advance if you want to buy from a farmer, as the farmer needs to know how many cattle to raise for sale. The selling price generally depends on the hanging weight.
If you buy from an abbatoir, you typically need to pay a fee for slaughtering the animal and cutting the meat. This is a good option to take if you want to try more unusual cuts of meat.