Although most sellers are very honest, it is important to do your research. Be careful of words such as vintage or classic as this doesn’t necessarily indicate rare or even old. Yellow gold charms made in the 1970’s and into the 1980’s are often listed as vintage charms while they are not rare nor will they be particularly valuable in most cases.
If you are only wanting a small number of sterling silver charms, stick to odd numbers of three or five charms on the bracelet. This will keep it looking balanced but also allow you to evenly space them around the chain.