If you were looking for a trainer for EG, well, there isn't one. But you can cobble one together using Cheat Engine, which you can download from here:
http://cheatengine.org/

It's open source software, so it should be virus free.

Once you downloaded and installed Cheat Engine, you will also need the file I tried to attach to this thread, but couldn't. So just copy/paste the text below into a text file and save it as eador.CT or similar (keep the extension, though):

<?xml version="1.0" encoding="utf-8"?>
<CheatTable CheatEngineTableVersion="14">
<CheatEntries>
<CheatEntry>
<ID>0</ID>
<Description>"No description"</Description>
<Color>80000008</Color>
<VariableType>4 Bytes</VariableType>
<Address>Eador.exe+15CEF0</Address>
</CheatEntry>
<CheatEntry>
<ID>1</ID>
<Description>"No description"</Description>
<Color>80000008</Color>
<VariableType>4 Bytes</VariableType>
<Address>Eador.exe+15CEEC</Address>
</CheatEntry>
</CheatEntries>
<UserdefinedSymbols/>
</CheatTable>

This is what you do: start Cheat Engine and Eador Genesis (doesn't matter in which order, they both must be running), start your game and Alt-Tab back to Cheat Engine.
Load Eador.CT (File>Load).
Now click on the "Select a process to open" button in the upper left corner, and select "eador.exe". Answer "Yes" if it asks you whether to keep the current list.
Now you will see the gold and gems in the list below, and you can change these values by double-clicking on them. And that's it!

Disclaimer: this works in single-player games. No idea about campaigns or multiple player.

Editing the 'Difficulty Var' file with a simple text editor is alot easier.

Edit: I didn't mean to hyjack your thread ;) but I never had any luck using a hex editor or trainers. Cheers!

That's why I posted this file - I did the work for you, you just have to read it in Cheat Engine.

I think you didn't hijack the thread at all. Thank you for your contribution.

I had a look at difficulty.var. Yes, it's much easier to edit that, I agree, but it doesn't work for games that you started earlier (without editing the file). In the rare case that your current game is too difficult - you an add an arbitrary number of gems and money with Cheat Engine and the memory map I prepared.