You can't go far wrong for £5, but this -
1) get another second hand Etrex Legend HcX. There is one on ebay atm £99
I don't think this is a good option any more, I think you would have to be very lucky to obtain a good HCx second hand now. Maybe if it's a 'refurbished' item from a reputable vendor.
Sheila and I have 4 HCx models between us (we each take a spare when on tour - often it gets lent out so we don't actually have to carry it far) - two of these are as new as they can be, that is, bought as end-of-line stock - but all four are now flakey to some degree and liable to cut out on bumpy roads.
Really, we're almost in the same situation as fboab now, though we haven't got to the external power stage.
I also have an E30 but I do find there is lots not to like - I've toured with it 3 times but each time I went back to my spare HCx, flakiness and all, mid-tour. But for the future I honestly don't see much alternative to learning to love the E30.