NTLite often runs sales. Furthermore, the "Legacy" license (€79.95) is a one-time payment—not a subscription. If you are a student or technician, consider the cost of your time. Fighting malware for six hours will cost you more than €80 in lost productivity.
NTLite does not offer a standalone ".portable" file, but you can create a portable installation, allowing you to move the program folder between computers while retaining settings.