Careful, if they have the #2 plastic identification number on the bottom of them, there is a high chance that they will warp over time. They don't hold up well to the detailing supplies except for water based items.
Look for the #3 plastic identification number. If you turn over a lot of your detailing bottles, they will have the #3.
Just because the bottles are cheap doesn't mean that they will make a good buy in the long run.
I get great use out of the 8 ounce ones from US Plastic. 0.54 a piece plus 0.08 cap:
Clear PVC Round Bottles with Caps - US Plastic Corporation
White Flip-Top Cap - US Plastic Corporation