how to write these sentences in English?

我正在考慮買不買這本書

I am considering ( or thinking ) whether I should buy this book.

我還在考慮買不買這本書

I'm still thinking about whether I should buy this book.

我要考慮買不買這本書

I need to think about whether I should buy this book

I am considering to buy this book or not.
我正在考慮買不買這本書


I still consider to buythis book or not.
我還在考慮買不買這本書


I would like to consider to buy this book or not.
我要考慮買不買這本書