This was supposed to end on Friday but is still alive & kicking. You can also get:
Prices in USD
O&O Defrag 21 Pro for 1 PC - $10.00
O&O Defrag 21 Pro for 5 PCs - $20.00
O&O Defrag 21 Server Edition for 1 Server - $49.00
O&O Defrag 21 Workstation Edition for 1 PC - $10
Keep prices in USD for the best deal.
Download & install & run the trial with all features for 30 days for free to give it a try & then you can buy (these are lifetime licenses)
You can download from here(oo-software.com)
Do you really need defrag?
Most modern PC's have SSD and you don't really need to run defrag anymore.
Even if you need it, just get free alternates.