Is it 'buy-in to', 'buy into', or 'buy in to' in the following sentence

Question

"I don't understand why people <insert words here> products that have a reputation of hardware failures."

What is the correct way to form this sentence?

Answer 1

This is the correct form:

"I don't understand why people buy into products that have a reputation of hardware failures."

See 15th definition of buy on Dictionary.com:

15. buy into, to purchase a share, interest, or membership in: They tried to buy into the club but were not accepted.

There is also a slightly more metaphorical, but not uncommon, sense of this phrase, listed in thefreedictionary.com:

2. Informal To believe in, especially wholeheartedly or uncritically: couldn't buy into that brand of conservatism.

Answer 2

Buy-in is a noun, meaning:

the fact of accepting a policy or change because you agree with it
If you want to make major changes you need buy-in from everyone in the organization.

To buy into something, a verb, means:

to believe something, especially an idea that many other people believe in
She had never bought into the idea that to be attractive you have to be thin.

It would be possible to write your sentence with "buy in to", but this is not common:

buy-in to 9 (these uses are still as a noun, just located before "to")
buy in to 18
buy into 845 occurrences in COCA

Note that this search includes transcripts of spoken English as well as various written sources; you shouldn't put too much stock in the exact numbers, but the trend is clear. Readers will understand if you write:

I don't understand why people buy into products that have a reputation of hardware failures.

Answer 3

I would say that it should be "buy in to".

A very similar question was asked in "Log into/login to/log in to", which I believe applies nicely here as well. And in that answer, another question/answer was referenced ( "into vs. in to") which also seems very relevant.