I just bought the game and read the rule book. There is one question:

As far as I understand it, the trade count cannot drop below the coin count by researching. So let's say I have 6 or more coins and the exact same number of trade and want to pick up a level 1 tech. Can I basically take it for free?

I tried to look it up and it does not seem to violate any rule. There is just an example where coins are used to save surplus trade so that the full price for the tech has been paid.

If I read your question correctly, then yes, you can get it for free.  The coins just are trade that when paying for a tech you are allowed to keep.  Keep in mind, though, you have to spend ALL of your trade when you buy a tech.  So, in the case where the number of coins you have equals the number of trade you have AND you have enough to pay for the tech, then you get your new tech and stay at the same trade level.

thx, that answers my question ;)

Also keep in mind that having say 7 coins, 6 trade and researching a LVL 1 tech will NOT get you up to 7 trade since having coins may never increse your trade when researching. The X coins you have  simply lets you keep UP TO X trade.

Also while you gain coins by different means, you should remember that coins gained by a tile (there are only two) are kept only while you 'control' that tile. Should you lose that tile then you forfeit that coin. In case yoiu weren't aware.....

kcjones2000