Can you please tell me what you think of my market research survey?

I think you will get a failing grade on it. There are two huge problems with it:

1. It's biased. It operates from a premise that the person taking the survey reads books. You don't have any question about whether they read books or if they like to read books. You force people to answer as if they like books, asking whether they prefer physical books or ebooks. What if they don't prefer books at all? Never mind that you should have said "paper books" rather than "physical books" because an ebook has a physical presence as well. Likewise, you then assume again that that the survey taker reads when you ask them if they snack and drink while they read. Those kind of leading questions constitute bias and, according to the standards of quantitative analysis and statistics, automatically void the results of the survey.

2. You assume people know what you mean by "subscription box." That is not a generally understood term, and you have failed to define it, so it means nothing to me and nothing to people who take the survey, or if it does mean something, you have no control over what it means because you have no way of knowing that survey takers understood it how you meant it because you failed to define the term. For example, some people may take it to be analogous to a Netflix subscription, meaning they have to ship the book back, but others may take it to be analogous to a book club subscription where they're sent a book every month that they get to keep, and yet others may take it in an entirely different and unpredictable way. Even just using the first two examples, the difference between being able to keep the book and not being able to keep the book and having to return it is a huge discrepancy that would make a difference to people taking the survey when answering how much they would be willing to spend, so the answers you get to that question become void. It's for these reasons that surveys must be free of jargon and only use lay terms, terms everybody understands. Since you used such a specialized and undefined term as "subscription boxes" that is not commonly understood, that also voids the results of his survey.

Those are fundamental problems. There are other problems as well. There are language and grammar problems, like failing to put the apostrophe in "months" to make it possessive, failing to pluralize "snack," and failing to put a comma before "would"--and all those mistakes are in just one of the 10 questions. There are also problems with syntax, like asking the survey taker how much they would "charge" when you really mean to ask how much they would "pay," or are you asking if they would go into the business of selling these so-called "subscription boxes"?

Basically, as a market survey, this does not pass muster. In fact, it's a total failure.