The money you receive in the dungeons are strictly used for buying resources. Unfortunately, that money cannot leave the dungeons, due to them being "tainted".
from the dunginering tutor
Equip your dungeoneering ring, then right click it and open the dungeoneering tab. Go into the tab and click "Form Party". Then go into the dungeoneering room, and 3 NPC's will be standing by each other, next to those people will be a small entrance. Click it, fill in the stuff and you will be dungeoneering by yourself.
drink the antidote
Yes.
The deepest level floor available to non-member RuneScape players is floor 35. Floor 35 can be accessed by players after reaching level 69 Dungeoneering (about 650,000 experience in Dungeoneering).
you get it from dungeoneering for 34k or 44k tokens
Red and Gold band.
You can only get dungeoneering tokens by getting experience in dungeoneering - that is, by completing dungeons, alone, or in teams of up to 5 people.
You go behind the bank in Al Kharid (east of Lumbridge). There is a boat there that takes you to the Dungeoneering place.
In the Dungeoneering minigame. Where they spawn is random.
The highest level for all skills except Dungeoneering is 99. Dungeoneering can be trained up to level 120.
You don't. You might notice that the name of the money is different: "rusty coins" instead of "coins". You can't take anything (or almost anything - there are a few exceptions) into dungeoneering, or out of it. The money in dungeoneering is used exclusively to advanced dungeoneering. For example, you can buy arrows, rune essence to make runes, raw food (which you must cook), or ores to convert into armour and weapons.