Olympus EX-25 macro tube - buying question

Hi there! I own an Olympus E-300 with the 14-45 mm and 40-150 mm lens, and also the FL-36 R.

I always wanted to try macro photography, and I've stumbled upon a EX 25 macro extension tube for sale at the price of 65 euros. It is used, but the seller says it is in perfect condition. Do you think it's a good price? Maybe it's relevant to say that I live in Portugal.

Thanks in advance.