My first response would be to save money for spells cause they'll use up a lot of money and caster's arent as limited by equipment as melee.
20p is tough... The best bang for the buck at a low level is usually HP/AC rings.
Unfortunately, the better ones cost 250-400p per ring and even the
worst one is still about 50p per ring (+2 AC, +30hp).
The only thing really in that price range is like
Kobold hide boots.
However, if you auction in EC tunnel about spending 20p for some stuff, a lot of times people will sell you something at massive discount for new players.