cost depends on app. because some apps has lot features. and works more fast compare to other apps. so like that apps cost more high like $200000 also this some apps cost. and some apps cost very low they had fast respond feature but cost very low like $1000. generally apps cost depends on performance, speed respond, and working fast.
first we have to plan which books we want to read.later buy that kind of books.generally books are read for increasing brain functionality, and decreasing stress.we kept aim to read 30-40 pages per day.that's around 45-60 minutes of reading each and every day. so we have chance to complete 50 books in a year.