I came across this site www.oblockbooks.com where parents could purchase educational material, which is used in preschools and schools for Kids.
I havent checked out the site thoroughly, but looks like the prices are reasonable.
There is also another option where we can buy it between a group of moms and create copies of the worksheets. If we think that might help us save some money and ofcourse if it is feasible. Just a thought.
Also if anybody is aware of anymore such sites, please share it with others, it will be helpful.