Yes all of "by", "in" or "to" mean this. "By" is probably the most common.

The word "cut" is going to need a direct and indirect object and so will need a preposition. Some other formulations can avoid the preposition by using "half price" as a phrase.

The seller made it half price

Yes all of "by", "in" or "to" mean this. "By" is probably the most common.

The word "cut" is going to need a direct and indirect object and so will need a preposition. Some other formulations can avoid the preposition by using "half price" as a phrase.

The seller made it half price

It's worth pointing out that for numbers other than half "by" and "to" mean different things, and "in" would not be used.

The $30 price was cut by a third. It's now $20.

The $30 price was cut to a third. It's now $10.

Yes all of "by", "in" or "to" mean this. "By" is probably the most common.

The word "cut" is always going to need a direct and indirect object and so will need a preposition. Some other formulations can avoid the preposition by using "half price" as a phrase.

The seller made it half price

Yes all of "by", "in" or "to" mean this. "By" is probably the most common.

The word "cut" is going to need a direct and indirect object and so will need a preposition. Some other formulations can avoid the preposition by using "half price" as a phrase.

The seller made it half price