An egg shell won't smell, unless it's put in an anaerobic situation.
Re: cutting cost corners when raising children. Kids grow so fast that they sometimes outgrow an outfit before they get a chance to wear it. Used or borrowed saves a lot of money, both clothing and baby furniture. Breast feeding... you can't get any more cost effective, or time efficient than that. No formula to buy, no bottles to buy or wash. You don't have to worry about what kind of nipple to buy... It's always the right temperature and flavor! Home made baby food... Have you ever tried the stuff in those little bottles that masquerades as baby food? Neither my kids or my grand kids would touch the stuff. One of the wisest investments I ever made in the way of baby food prep was a "smart stick" (immersion blender). Baby can eat what ever is on the adult menu... for the most part, after initial trials to test for food allergies. sorry... no one asked for advice... every once or twice in a while I venture an opinion, when none is asked!