Congratulations Ann on becoming a new mom in a few weeks!
I would take the advice of the mother who suggested breastfeeding. It has so many benefits for the baby and for you; baby receives your antibodies, less ear infections, less prone to allergies, formula is expensive and may actually CAUSE asthma and other allergies. Also mom's who breastfeed are less likely to get breast cancer. These are just a couple of reasons to breastfeed. There are a ton more that are just too numerous to name.
To find out more, go to www.llli.org.
Also you can speak with a lactation consultant at the hospital where you deliver or take breastfeeding classes.
If you decide not to, make sure you buy bottles that are BPA free. This harmful chemical is banned in California. I just wish the rest of the country would catch on too! BPA may cause early puberty and cancers that are "hormonal" such as breast, ovarian, and testicular cancers. Do NOT sterilize bottles that contain BPA, as heat causes the chemical to leach into the liquid that is given to the baby. Also if you decide to breastfeed, don't take in any of these liquids yourself as they are passed through breast milk.
The healhthiest and least expensive and least time consuming way is breastfeeding; the safest way to go as far as bottles is BPA free.
To finally answer your question, you only need to sterilize the bottles the first time, after that, just handwash and air dry.
Good luck and Congrats!!