This is a great question. I love it because many small businesses don't even have a strategy or don't consider asking someone to review. Congratulations!

To answer this question, i find it very difficult because it depends on too many aspects. It is like asking how much would a car cost. Do you mean a Mercedes or a Toyota? 

I can give you my own price because I dont want to mislead you. 
For us, it will be cca an hour with myself or my partner, and this would be $497 - and it would be disscussion rather than reading a document. 

Reviewing a document is way more difficult to price because it depends on what the document is and how much research needs to be done outside of the info there. 

We prefer to do an audit combined with the review of the strategy so we better understand the business. This may be cca $3,000. There may be money to be made easily which can come out of that audit and cannot be seen in a strategy that was done without an exterior eye. 

Hope this helps. and if you need further assitance, pls have a look at this video 
https://www.ozanagiusca.com/en/shop/consulting-services
It is about maximising the company's value and you will understand what is missing from what you have already. 

Of course, would love to help you further - just get in touch. 
ozana