Undies are a great introduction to sewing lingerie. These Binky Panties by Evie la Luve are beautiful and comfy. There is a bit of finesse needed to add the elastic, but I will teach you the technique to create smooth seams. Great beginner-intermediate class. I hope that you enjoy making these so much that you will try some of her more intricate patterns.
Where to purchase supplies:
All supplies can be found at local fabric stores, and maybe even your scrap pile.
Evie la Luve sells some great kits, and there are quite a few lingerie kits on Etsy.