Some noob questions.

Great game so far, been soloing tier 1 a couple of times, have tier 2 armor and a tier 3 weapon.
And how I've hit critical mass on questions.
First off whats a good way to find out how much something is worth? Asking people when they want to buy it from me usually yields some absurdly low number of crowns.
I hope to obtain the Angelic armor, how do I go about getting it? What types of monsters drop the recipe if any? Do I buy it from a vendor somewhere?
Same question for Cold iron weaponry.
In tier 2 and 3 does it pay off when entering a fire zone to equip some fire resist armor? Or can you get by with regular stuff?
If I can solo tier 1 with no deaths, not even on level 7 arena fights, will tier 2 be a death-a-thon it says it is? Or is it soloable with some effort?
Is there any way to change your knights color? Just curious on that one.
Thanks in advance.
You can really never know how much something is worth as they are constantly changing. You can get the angelic recipes at terminal 2 (its halfway through t2). It may take you a while to finally get it as the merchant's recipes are random everytime you enter the terminal. T2 is soloable, as I have been soloing it. It is not recommended to try and solo bosses (such as the jelly king). I can basically get all the way through T2 except for that last boss level with 1 death maximum. You can send me a tell ingame, if I'm on, about any price questions you have and I'll be able to answer them. My name ingame is Blueman. Feel free to send me a tell anytime.
Well for the material prices there are some opinions here in this thread http://forums.spiralknights.com/en/node/2216
By Angelic armor I'm assuming you mean Angelic_Raiment(http://wiki.spiralknights.com/Angelic_Raiment)? In which case you would be able to get the recipe from Basil at the terminals, not sure if he sells the recipe at terminal one but I have seen him sell it at terminal two, if you don't see him selling the recipe keep in mind that his inventory is suppose to be random and changes daily.
Not sure about the Cold Iron weaponry questions so I'll leave that for someone else
Tier 2 is solo-able but you just need to play a bit more cautiously, although I'm not sure about the boss fights but I believe some people have solo-ed Tier 2 at least
I don't believe you can change your knights colour