John Q. Mayhem said:
A couple of +1 arrows are a lot cheaper than a +1 spiked chain, and there are some CR 4 encounters that have DR/magic, I'm sure. A bow or some such is a good idea because, as a 2nd-level sorcerer, he's only got about 5 1st-level spells/day.
Frankly - I think +1 arrows are probably the worst weapon this character could buy. A scroll of magic weapon comes in at 25gp. Each +1 arrow costs 40gp. +1 arrows suck hard.
I'd agree that a ranged weapon is probably a good idea though - but don't spend serious cash on it.
On another note, a hat of disguise ONLY DISGUISES you. It's not "alter self all day long".
My suggestion for this character would be
1. A bunch of scrolls for one-off situations. Magic weapon, comprehend languages, expeditious retreat, floating disk, hold portal, protection from X, silent image, unseen servant are all good 1st level spells that you probably don't want to waste spells known on.
2. A magic version of your primary weapon.
3. Some sort of armour. Your choice on this has a lot of options depending on what spells you know. If you have, and intend to use, mage armour then get some non-armour boosts to ac (like an amulet of natural armour). Otherwise: if you don't use somatic components often, just pick up a +1 chain shirt, and something else defensive. If you do, a +1 mithral chain shirt.
4. Healing potions.
5. Something cool and cheap. I always like the cheapest bag of tricks - just something fun to do once in a while.