Amazon has the Anchor Hocking Glass Custard Cups with Snap On Lids, Set of 4 for $5.35 with FREE Super Saver Shipping and $35 purchase or FREE with Amazon Prime.
These are oven-, microwave-, and dishwasher- safe.
Perfect for baking small desserts or for storing leftovers.
Pricing was current when the post was published, however Amazon prices change often, so please check before you buy.