Larger online dealers like Apmex, SD bullion, Scottsdale mint, etc. are reputable. If you buy from ebay, I suggest sticking with US "junk silver" dimes, quarters, and half dollars that are dated 1964 and earlier since they are almost never faked and you are more likely to buy fake .999 silver on ebay. Ideally, you buy from a local dealer in person.
Larger online dealers like Apmex, SD bullion, Scottsdale mint, etc. are reputable. If you buy from ebay, I suggest sticking with US "junk silver" dimes, quarters, and half dollars that are dated 1964 and earlier since they are almost never faked and you are more likely to buy fake .999 silver on ebay. Ideally, you buy from a local dealer in person.