I find myself wanting/needing a couple of pickups for a guitar and violin.

But I'm cheap and I don't use an amp. So specifically, I'm looking for decently priced pickups that can plug directly into my PC one way or another. Can anyone recommend any brands/items that might suit my needs?

Are you trying to record acoustic instruments? If that's all you're trying to do, it'd probably be easier to just get a decent mic and record with it rather than fiddling with pickups.

For guitar, yes a good mic. For a violin, nay.
A pick up would be more useful to record violin, they don't usually work guitars because the vibration distorts the sounds and gives a really metallic input but that's not the case on violin.

I do not know of any pick ups or anything.