And, think of us guys overseas, we look at parts and often pay the sellers asking price because we don't have the options the guys in the States do. Then when we want to pay...no credit card facility, no paypal, they will only take cash or a money order, which cost us guys in Oz about $28.00. Then we have shipping at quite high rates.
When I hear cash only, money order only, no paypal, I think sometimes a little churlishly (I admit) 'why the heck are you bothering'. The easier a seller can make a transaction the higher the success rate will be.
On the other hand, tyre-kickers are a fact of life, they'll always be with us. And while a follow up note or word is nice, none of us should be surprised when for most people, that moment has passed. Be professional, or if you can't do that be philosophical lol, or simpley move on.