Right now on Amazon you can grab this Philips AVENT 9 Ounce BPA Free Natural Polypropylene Bottles,3-Pack  for $14.03.
- Nipple is soft and breast-shaped to promote comfortable latch-on
- Twin valves prevent babies from swallowing air to reduce colic
- Ergonomic bottle is easy for parents and babies to grasp
- Wide neck makes filling and cleaning easier
- BPA free polypropylene material is easy to sterilize
These are around $19 at Walmart so this is a VERY good price.
Be sure to double check the price before you buy- Amazon prices change quickly!