Systems Management

I was just curious if anyone that may use a software like this knows of a good and less expensive alternative to UserLock?

http://www.isdecisions.com/products/userlock/

Working in education I have been asked for reports and data on our computer usage and it is near impossible to get historical data of who has been using what computer like what time they logged in/out and how long they used the computer for.   I came across UserLock in a previous job and found that the software offered such features by simply taking the data from active directory and keeping it in their own little database which can be used to get nice clean reporting data that I can give to my teachers and administrative staff.

It also has other features like user lock out and limiting to certain computer groups/labels and limiting concurrent logins.

I have tried to search for alternatives because my organization is having a hard time with the cost of UserLock and wanted to see if there were less expensive alternatives that can give all or some of the features particularly the historical usage data.

Thank You in advance,