L2.NET is not sold, it is given away for free. Even so, it takes hundreds of hours and lots of patience to make this program.
L2Walker cards are $7 USD per month per account. For one account that is $84 USD a year. Two accounts will run you $168 USD per year. L2.Net is infinitly cheaper than L2Walker.
In return for your modest donation of $5 USD, you will be given an L2.Net Product Key that unlocks several donator only features.
L2.NET Donations are used to buy software for development of L2.NET. As well as provide motivation for me (slothmo) to work on L2.NET.
The more donations recieved, the more work done on L2.NET.