Finding a good set of antique crystal door knobs is not easy especially if you are insistent on doing your shopping in traditional brick and mortar stores. Most stores like Home Deport or Lowes offer a fairly decent selection of door knobs for sale and they may even offer some antique crystal door knobs however the selection will almost surely be extremely thin. If you want to have any kind of selection to choose form and if you want to make sure you can find a good price on your door knobs then you have to do your shopping online where specialty retailers can offer more variety and knob for your dollar.
For more on this topic see my other articles:
Cheap Dresser Handles And Knobs
Buy Oil Rubbed Bronze Cabinet Hardware