Ray of Light is 12,5 k to sell.

So just sell every third, and break the first and second. You make 500 gold on the transaction, plus whatever runes/crystals you get from two breakings, + whatever you gain in the keeper fight. With bloodthirst you can also always use Christa's gold during the fight to gain additional money.

Yeah, this wasn't thought out... heh.

Edit: Oh, and with the right combo of units/skill, you can easily gain back the 40 mana while fighting the keepers, meaning you don't even have to wait around for your mana to replenish. Score!

Now I have to figure out how to get better gold from Christa, it kinda varies wildly from 400 to 8k+ and for the moment I'm anyway using the fights to get the no rage achievement
There's usually a shooter unit witch I dwindle down to just a few and with level 3 concentration it's just defend defend,defend till the 10th turn

Not sure if you meant this, but literally: SCORE! Infinite keeper fights without needing to spend game time in between them means that high-score games now can get all the XP they want. So to recap:

Infinite Gold
Infinite Crystals
Infinite Runes
Infinite XP
Zero (game) time spent.

Game mechanics like these kinda make cheats obsolete.

Well, that's assuming you've got lots of spare time. Frankly, if I wanted lots of runes/gold/crystals/whatever, and I don't mind cheating, I'm still going to fire up Cheat Engine because it's a heck of a lot faster.

True that. As much as this combo is amusing, I can't imagine taking the time to do it hehe.

I am actually a little surprised that recipes aren't one-use items. It makes sense that you could write them down though, and it's too bad you can't add them to your book. The second crafting dialog says "Add the magic recipe." I thought it would put it into a new recipes section of my spellbook, but that's apparently KB-speak for "close the menu." :)

I already imagined that the upgradeable, craftable Silver Rapier (which I got early in my current game) would be broken; nice to see it spelled out... but of course, taking the (real-life) time to abuse this exploit seems rather silly, and it is probably a lot more satisfying to earn the various achievements one can get elsewhere. I can't imagine that it will feel like an accomplishment this way...

Still, yet another example of a game mechanic that was poorly executed and/or poorly tested. Maybe making recipes disappear after one (or a few) uses would be a natural solution, even if it doesn't really make sense.
edit: Right, I completely missed that this was mentioned right above this post. Shame on me.

Sorry to bump this old topic but if you have even chance for 2 runes OR 6 crystals then you get need 2 crafts to get in average 2 runes + 6 crystals. But for 2 crafts of lvl 3 items you need 2x(16 crystals+1rune)=32 crystals+2runes.
How then the ratio becomes 1:1.5 (1.5 runes income for each 1 runes used for craft)?