Candle of Invocation. Never know when an extra planar gate on the cheap might be useful.
technically everything is up to your DM, but there are definite guidelines as to how much wealth you should have. If your DM follows these guidelines, I expect you'll have more cash available than you expected.
Before I get into that though, allow me to suggest you change your build. It's probably best if you go Ranger-8 and take the trapper archetype. You will trade your ranger spells for the Rogue's trapfinding ability. Spells can be a bit much for first time players anyway.
Anyway, to answer your question I would probably grab some items to boost your str, dex, or con. All three of these stats are quite good for you.
Weapons: you'll want a magic longbow, at least +1. Make it composite with a strength rating equal to your strength modifier. You'll want a magic faclchion too. At your level, magic is more important than getting it made out of special material. Adamantine is great vs constructs and an expensive waste vs everything else. I wouldnt worry about it. If you like you can get some Adamantine-tipped arrows and pull those out in case of a construct, otherwise just use steel weapons. This will be a lot cheaper for you and probably just as effective.
You'll definitely want a magic breastplate too. The higher you can boost your armor class, the better.
Get a Cloak of Resistance. No exceptions. Get this on every character, you want to have high saves.
Other items that are nice to have are: Amulet of Natural Armor/ Ring of Protection (these both increase your armor class further), Handy Haversack (item storage), antitoxins (cheap and just might save your life if you are poisoned), elixer of water breathing (never know when that might come in handy), potion of fly (that too), always have rope and a grappling hook (why not?), Jingasa of the Fortunate Soldier is very useful if you can afford it.
If its core only the trapper archetype would be out.
Like awp said, if your GM follows the wealth guidelines you should have 33k gold to spend. Not all GM's follow that exactly though.
On top of the things awp mentioned I think a Ring of Sustenance is a good thing for at least one person in the party to have for keeping watch at night. It's pretty cheap, so you could enchant it on top of another ring for a little more.