First of all may I say a huge 'thank you' to GOG for making the game available. My question is - how on earth do I get enough money onto a character to buy the above item. I have enough coins / jewellery spread over all 6 chars to buy one, but I can't get 5000 platinum (i.e. 25000 gold) onto one char as they become overburdened. I have tried stripping / trading all items to the other 5 but that didn't help :( They are level 3 with 18 Con, will they be able to carry more as they level up, or am I missing something really simple.

All help will be much appreciated.

Already answered this for you:

https://www.gog.com/forum/general/pool_of_radiance