The little babe now has a nice little stash of padded underwear for daytime wear along with three new fleece covers. Running around outside, or even inside as long as I'm watching for when he goes, he doesn't need a cover. There are thick enough to absorb urine but not so bulky as to make them uncomfortable for a little mover and groover! I did the gerber training pants route with our oldest and these beat them hands down, not even a good comparison, blows them outta the water (not that I'm tootin' my own horn or anything here :) ).
Cost-wise these cost me $8.59 to make 10 pairs of padded underwear and three fleece covers. The only thing I had to buy was the underwear, the rest came from my fabric stash. The cost would have been approximately $25 if I had to buy the materials (FOE $1.50 for 3 yards, fleece $7.00 for 1 yard, flannel $8.00 for 2 yards and underwear $8.59 for 10 pairs).
As far as sewing, they are very quick to sew up. I did 10 pairs of underwear and 3 covers in about 2 hours and that includes the time spent measuring and cutting materials.
You could use any type of material for the cover (fleece, wool, PUL). If you used a pattern such as Katrina's Soaker Pattern (free pattern), it would eliminate having to use foldover elastic.
Hope everything is staying cool. Temperatures here in Wisconsin are hoovering around 100 degrees!