I haven't actually done this with VHS but have digitised vinyl, and I had to buy a £12 USB soundcard with a pre-amp on the RCA input, this is what the turntable plugged into. I then pointed Audacity at that sound device and hit record before playing the album. I'm assuming that it's a similar process but with different adaptors and software.
So my assumption is you'll need a physical connection between your source (which I'm assuming is an old VHS player) and the laptop, which would have composite or SCART on one end and USB on the other.
Why some of them are £20 and some of them £80 I don't know.