Ive bought many coins\bullions off here, and my one word of advice is, DO NOT buy without a personal picture sent, always ask for halmarks on things, or dates. I have had some fabulous items off here coins and bars that are amazing quality and genuine, and some that are not.
I have always collected coins, and bars, and will carry on collecting, never let one mishap on here stop your hobby, as their really are some diamonds amongst the rough.
The older they are, and the better condition, generally the more worth they have, and there a fascinating item once you own coins from different countries, and you can also obtain ones from the war. If you ask any older people in your family, im sure they will find you some from years ago to observe.
I could give many words and advice about coins and collectables but I'd be here for a while to do it. I have had an interest in this for many years and tend to have a lot of good experience.
My favourite coins are the oldest and best conditioned ones, also the ones from Africa in olden days. However like I said earlier, buying a coin or anything over the Internet requires good knowledge and experience or atleast photos to prove, if all is good, go for it, go coin crazy!