Hi. Well, I just boiled water and dropped the bottles in. Never had any problem and it sure was cheap! :>)
I also washed the bottles in the dishwasher and had one of those baskets you hook on for the nipples and rings that go around the top. Have to say that this is what everyone in my friends circle did with no issues.
good luck!!
This is also discussed on the 'Baby Products' forum here on MH
You need to make sure the bottles are michrowave safe and BPS free,, glass bottles are safest , I suggest that you do some research as there are many opinions out there. Amazon.com have a range of sterilizers go to www.Aamazon.com also try this link babybottlesterilizerinfo.com/