On Amazon right now you can get these handy Diamond 50 Count Multi-Purpose Mini Cups With Lids, 2 oz, Clear for just $4.68! This is just $0.09 per cup. These are great for packing lunches.
These will ship free with Amazon Prime or qualifies for free Super Saver Shipping with a $49 purchase.
Note: Amazon prices and promotions can change at any time. The price(s) listed in this post is/are subject to change.