yes, it really does depend what you want to do with it - for a machine worth only £80, you won't get anything that will last.
There's an offer in Good Food magazine this month (June issue) for a toyota machine worth £200 for £99.
that's the kind of thing you should be looking for if you want it to last a while - especially if you're planning on handing it down.
If you're only using it occasionally, then yes, a cheap machine is fine, but if you're planning to use it often, and for heavy stuff (bear in mind that even a thick cotton is heavy for cheap machines), then you'll need to spend a bit more.