without a dedicated buff bot its easily going to cost over 3k as a frontliner holding the line.
heals, barkskin, prot evil, haste, strength and con (these are pretty standard, sometimes other stuff is nessecary, sometimes a deathward). Most of these need like 2 or 3 in the time a quest is completed (Unless you just run through it all)
Even with a buffbot it can spill over a thousand on heals. Quests are simply for XP, the loot is rarely usefull and the gold only ever gives a minor return on what was spent. But like I say, I know this is only for a frontliner who will only on occasion get buffs that has no magical capabilities. I know some pc's can sit in relative safety, expend very little actual gold for questing and be able to buff/heal themselves without actually spending anything.
There is no incentives for people to buff frontliners, I've heard it stated a few times that those capable of such would often prefer to buff their own summons or perhaps cast other things (this is fine, they do what their characters would). So while this is the case you are going to see a massive inbalance in what people have goldwise. Crafting is the only way to sustain ones self in terms of what the features in game offer (DM events and plots can do this aswell) and crafting is a huge timesink I would rather spend my limited time IG on other stuff.
Big events I have seen allways seem to get a payoff in, whether its consumables or gold. People tend to be more willing in buffing others at these points aswell, but due to the nature of some of them and the combat going on for longer it can cost a hell of a lot more than quests do. (In the past there was rarely ever loot dropped from such things except perhaps consumables and the odd unique item here and there, but this is something I have noticed getting alot better in the past few weeks in my limited play times).
If I want to go exploring, I am pretty certain its going to be a loss. (Normally I have a reason to do this plotwise, its going to sometimes cost me similar to a quest and more to reward those who do come along).
The short of all this is to make RP freinds with a caster, they make life easier but this isnt allways an option. If no spell casters want to do whatever it is, its going to cost alot or risk death. No one wants the XP hit, so they will just avoid coming along in favour of grinding out the crafting which can make them the gold they need to survive the events. Things that can help with this is perhaps cheaper class specific alternatives. More loot designed to give none spell casters a slight boost to close the gap alittle and negate some of the expeniture ( 1/day Imp Inv/barkskin/stoneskin/shield etc) as while this wont put these weaker classes on par with spellcasters it will certainly make them more viable (this is afterall the age of magic and these lvl 15 characters spell flingers should be more powerfull than the grunts and warriors)