Lebanon
Half Piastre coin is from CYPRUS country(see Europian Union countries).
Ecuador
??? What denomination? What country? If it's a U.S. coin, what mint mark? Please post a new question with those details.
It doesn't come from any particular country.
The coin could have come from many of the then, British Empire countries. If the coin has no country name on it, it is most likely British.
The one I have says Espana (Spain)
It should have the country's name on it. Most likely you'll see Espana, which is Spain (in Spanish)
There is no such thing as a British 20 dollar coin. If you have a 20 dollar coin it must come from some other country (or even British colony)
Well depending on where you live, the best place to go would be a coin show. If you live in Los Angeles, the Long Beach coin show would be the best option. Coin dealers come from all around the country to sell at this show. And ancient coin dealers are abundant.
I believe your coin is from Bulgaria.
If the coin has no country name on it, it is British, otherwise, it could have come from any of the 50 plus British Empire/Commonwealth countries.
Well, I'm not a coin-collector but a numismatist. The description you gave, makes it certain that it is a coin from Thailand.
Diez Gramos is an old Spanish coin and comes from Spain. Diez Gramos is Spanish for 10 grams.
The coin usually has the name of the country or ruler on it.
That depends on which country the coin is from.
Not nearly enough information. WHAT coin? What country did it come from? What's its date? If it's from the U.S., does it have a mint mark? All of those details are needed to identify a coin. Please post a new question that includes them.