limited funds - which spells are essential?

[Neon Archie]

Can probably skip Starshine and Halo of Light, these are spells that generate light sources which you may not need if you have infravision naturally.

Would skip Summon food / drink. Bind Forage to a command key like "A" and never run out of food/drink.

Would for sure get these type spells as priority:
Movement enhancers
Direct Damage
Heals
Thorn Coats
"Skin Like" line

Then get:
Endure lines
Animal charm / invis

The first 15 or so levels it can be a challenge to get all the spells when you ding. After that though you should start making enough coin to go back and buy the ones you missed, and it won't be an issue getting them all going forward

[Danth]

Level 9 you want Ignite and Light Healing as your two largest immediate priorities. Invis to Animals has use (in conjunction with charming, mostly) later on, but not right at level 9. Strength of Earth is used if you find yourself getting encumbered but you can live without it for awhile if need be. Enduring Breath also classifies as a spell you'll eventually want but won't need right away. In the case of the "endure" resist buffs and the damage shields (both self and targetable) there's a fair chance you'll buy later-level upgrades before you even use them. Firefist is pointless and Treeform doesn't get much use other than as a joke past level 14 because it strips off run-speed buffs.

For level 14 you should buy Spirit of Wolf, Levitate, Bind Affinity, Skin like Rock. Summon Food and Summon Drink are rarely used, but nice when you need them (typically when on corpse run) and very cheap. Stinging Swarm may see use if you root-dot stuff, contingent on playstyle. Befriend Animal has obvious critical use for Druids who wish to charm. I like to keep See Invisible up at all times on P1999 because I don't trust other players very much, but it's hardly ever needed for actual PvE gameplay. Anti-summoned spells and area effect damage spells can be largely ignored at this level--you'll have upgrades available before you ever need to use them. Invigor presently serves little purpose on P99 ; you can go back and buy it later if a future patch ever makes it more useful.

Danth

[DMN]

Might be a good idea to mention you plan to be duoing with a warrior primarily.

Treeform is actually quite powerful and underrated at this level range, especially if not soloing and you can have someone else pull the mobs to you. You might consider setting it up so the druid is tanking with a thorn shield up for these levels if you can effectively utilize treeform.

Weapons are also sometimes more important at those low levels. If the both of you had a 2h fine steel staff/sword, that might be far more useful investment at those levels for the plat investment(you should still certainly buy the ones you have asterisks on though-- you might be able to hold off awhile on bind depending on your location). Find someone killing guards and offer to buy one of them for a plat or 2 more than they'd vendor them for. Or if near qeynos you can do the bloodforge hammer quest. Not so great until level 10 due to the damage cap though. But they would certainly help out going after wisps early and if the lightstone quest it is, it would be a great source of early plat.