My tip is simple. Go to the hardware store and ask for the small felt pads that are used on the inside of cupboard doors. They are very tough, have great adhesion and they will allow you to put the iPad down on most surfaces without worrying about scratching your baby. The bonus is that you can still have a naked iPad. If you're like me, I just slide mine into a laptop compartment of my knapsack when I go out with it.
The other alternative is to get the kind of pads that are clear plastic made for the same purpose. They have very strong glue on them and they'll stay put. The bonus of the clear plastic ones is that they will grip a bit so your iPad won't take a tumble off the table should it get knocked. So that's my tip. Shouldn't cost more than a few cents. Compared to $40 for a plastic cover this is way smarter.
Let me know what you think in the comments.