I think the best budget friendly speakers I've read about are the creative pebbles? From what I've read, they're worth a lookOuch, bit expensive - most I wanted to spend was around 50 ish.
Not if you dont have spaceWhy are you putting speakers behind the monitors? They should be at the side of the monitors, and pointed inwards.
Not if you dont have space
Yes of course, dont cover the speaker drivers. It would be similar to placing huge speakers in front of the monitor covering the screen!Your speakers are not really covered up, at least the drivers are not covered, so they should still work reasonably well.