It depends on the brand & model. Some USB-parallel adapters have drivers only for older versions of Windows. You haven't specified what brand you're referring to.
You might want to check Amazon as an alternative. (Note, I have no connection with them.) At least then you could know what brand you're buying. I very much doubt that a $4 adapter would have current drivers, i.e. for Win7, since those usually go for about $20-25.
I have used one with Win7 but, as mentioned, it costs more. I see that Cables2Go makes some that are Win7-compatible, but there are also other brands.