Olympus E-20p External Flash?

Hello everyone

I am very new to this, but would appreciate any help and hopefully in the future may return the favour.

I am the owner of a wonderful Olympus E-20P digital camera and am very happy with it, but i am now wanting to buy an external flash for it. I could buy the FL-36 or FL-40/50 but they seem very expensive.

Does anyone know of any good flash guns from independant makers, that would work well with the above digital camera .

Thanks

Phil