Wizard Labs has the LDPE Plastic 50ml bottles for 59cents each. They have 30ml LDPE Plastics for 55 cents each. They come with the drip tip type bottle stoppers and child protective caps. They also offer quantity discounts if you are in the market for 50 or more bottles.
That is where I get my plastic bottles.
The glass bottles are priced better at amazon.com
30ml (1oz) 12 Pack of Amber with glass droppers are $6.08