It all depends on what kind of floor you are washing, what you should use.
I have mainly wooden floors that are varnished, plus tiled floors with ceramic tiles in the hall, bathroom and wash-kitchen.
I wash all my floors in old-fashioned soft soap in hot water, or if they are not very dirty just in hot water. As soap has been in short supply recently in our local shops, I have reverted to washing-soda in hot water.
Be careful of using vinegar on tiled or terasso floors or indeed any stone floors as they may be damaged irrepareably by vinegar, and never use bleach on any floor unless you are certain the floor can stand it.
If the floors look as if there is a film on them when they have dried, you probably used too much soap, so you will have to rinse the floors in hot water, using a mop or floor cloth that has not been in soapy water.
I never use washing-up liquid on the tiled floors as it tends to make them slippery.
I entirely agree that the special solutions for cleaning floors are a waste of money.