Check out your local bike coop/recycler. They often have piles of toeclips and toeclip compatible pedals. I prefer the plastic clips as they don't cut up the shoes as much.

With practice, you can always quickly get your feet out unless you're using plastic cleats on old racing shoes. Get used to them before carrying the kid though.

SPD clipless pedals/shoes are also worth considering. And, again, get some practice before loading up the precious cargo.