I recently purchased Antares software & found that I needed an I lok.I use several softwares but this is the first time I hear that a purchased software needs an Ilok.Can I use a USB flash drive instead? Or where can Iget the cheapest Ilok to work with this?
No, a flash drive won't work.
iLok is fairly common in the audio industry (interestingly enough none of the high-end video products ever use it)...Pro Tools and lots of plug-ins (Amp Farm, Pod Farm) use it when you aren't using specific hardware as an interface. But it sucks to spend an extra $50 for something for one piece of software.
If you look around, you might find one for roughly $35, check the Amazon marketplace prices.