I can remember years ago when my Mom would buy the new wonder spread called margarine. Previous to that it was sold uncoloured and came with a capsule to mix in to get the creamy yellow but really a bright, fake butter look. I have never, ever liked margarine. Margarine is made from a low quality, chemically extracted, refined vegetable oil that loses it's natural Vitamin E through heat processing. It also contains colourants and additives. I don't like the taste, the texture or the fact it is not a whole food so we use butter or olive oil in our home for cooking, baking or as a spread.
We don't eat a lot of sandwiches but most sandwiches we do eat do not have butter used as a spread. I often serve homemade French, French sourdough or sourdough bread with olive oil for dipping. It is healthier than margarine with a lot more flavour. The oil can be left plain, seasoned with herbs or you can stir in pesto or sun dried tomatoes.
The choice of olive oil is important. The darker the oil the stronger the flavour. I prefer a cold pressed, extra virgin olive oil with it's light, fruity flavour for this purpose. Pictured is the sourdough bread with olive oil dipping bowl I made for dinner. The olive oil was seasoned lightly with dried oregano and thyme the served with sourdough bread.
Some are tempted to make up extra of the seasoned olive oil. Don't do this especially if using fresh herbs or fresh garlic as there is a risk of botulism. The toxin that causes botulism is colourless, odourless, and tasteless. The amount of size of a pin head can make you quite sick or result in death. Make only the amount of seasoned olive oil that you will use for that meal. Discard any left-over seasoned olive oil. In this case the frugal choice is discarding the left-over oil rather than risking a potential food borne illness.