LINQPad standard edition is free to download and use.
LINQPad is not an open-source product and the source code is protected by
copyright laws. Nonetheless, you are free to disassemble the executable to
satisfy your curiosity. The author provides no warranties, and accepts no liability
for direct or consequential damages. Read full EULA
Licensing Notes on LINQPad 5
If you purchased a paid edition of LINQPad 4 prior to 1 January 2015, you'll need to
purchase an upgrade
to use the paid features of LINQPad 5. You can
find out here whether
your license covers V5, and the cost of upgrading. Upgrade discounts are available for
a limited time, and further discounts are available right now to raise the user count or edition.