Its the meaning stupid

Expression
Why it is usually a tautology
Why it may not be a tautology
"the reason why" or "the reason is because"
"reason" is already by definition a description of why something happens.
"Reason" implies a deeper insight into the cognitive cause for action. "Why did he cross the street there?" - "There was a crosswalk." vs. "What was the reason why..." subtly demands further explanation into the significance for the individual. Note: This use only pertains to cognitive (reasoning) entities.
"free gift"
"gift" is, by definition, something given without charge.
May be used to emphasize the fact that there is no hidden expectation of reciprocity.
"cheapest price"
"cheapest" means "lowest priced", thus "cheapest price" is actually "lowest priced price".Also it is almost a non-sense, as a price is not to be bought.
Using "cheapest" on its own may imply "low price, low quality", whereas "cheapest price" emphasizes that the sale price is the lowest without connotations of poor quality.
"first introduced"
"introduced" generally implies that it is the first time that someone or something has been presented.
A speaker may be introduced to different audiences on different occasions. It would be correct to refer to the first such occasion as being when that person was "first introduced".
"new innovation"
"innovation" is defined as something new.
In context, there might have been previous innovations.
"forward planning" or "planning ahead"
"planning" is always done in advance.
May be used to differentiate the usual planning from a different form of planning done well in advance. For example: "Besides planning this week's meeting in detail, we should also do some forward planning of next week's meeting."
"faster speed"
"faster" means "greater speed", thus "faster speed" is actually "greater speed speed".
"faster" may refer to either an absolute magnitude of speed (e.g. 90 km/h), or the time taken by an event. Mapping software is an example which allows for specification of preference.
"unsolved mystery"
"mystery" is something that is unexplained, unknown or unsolved.
This refers to other "solved mysteries", which are then not mysteries.
"added bonus"
"bonus" is an added extra, thus "added bonus" is actually "added added extra".
May be used when referring to an additional bonus. For example: "Buy two and receive a bonus pencil sharpener, buy five and receive an added bonus steak knife."
"over-exaggerate"
"exaggerate" means "overstate", thus "over-exaggerate" means "over overstate".
May be used to differentiate regular exaggeration from excessive exaggeration. For example: "Exaggerate the size of it a little bit if you like, but don't over-exaggerate it, otherwise you won't seem credible." Proper exaggeration would simply be emphasis, compared to overemphasis.
"short summary"
a "summary" is a "shortened" version of a text
May be used to differentiate a very short summary from one of average length.
In some phrases such as "I can see it with my own eyes" or "I made it with my own hands" the tautology is a rhetorical device that adds emphasis, as double negatives used to do. Expressions such as "all in all" or being able to "read and write" (to have literacy) are not strictly tautological and are instead referred to as siamese twins.