How much value does M/NM really add

[virtual]

I've been watching lots of auctions on ebay over the past few weeks, and I was wondering about a decent way to guage a card's value based on its condition.  PSA graded cards with high ratings seem to go for a significant amount more, but really beat up cards (lotii, etc) don't seem to lose that much value.  I realize there is a lot of variance on ebay because of the reliability of the sellers, but assuming that you have a decent baseline for a card in a particular condition, how much value does it lose by dropping on the grading scale.  (Lets use anycraze.com's scale for consistency: http://www.anycraze.com/card_quality.asp)  Also, what is a decent baseline to start with for NM condition UL power cards (or appropriate expansion).  Here's my thoughts on the baseline, they are pretty close, but a few might be off.  

Mox Ruby: 290
Mox Emerald: 260
Mox Jet: 280
Mox Sapphire: 320
Mox Pearl:  260
Black Lotus:  600
Time Walk: 300
Ancestral Recall: 320
Bazaar of Baghdad: 110
Mishra's Workshop: 150

[Mixing Mike]

If you ask anyone that I know, they'll say your prices are off.  Lotus goes for $600 AT LEAST.  You can get rid of any Mox for at least $250, and the big blue aren't even included.  They go for around 320-360ish, right?  Anyone disagree?  I'm also assuming M/NM conditions.

[virtual]

I was basing my guesses off MOTL (which is a bit low) and looking over Ebay.  Also, I wasn't using NM as my baseline.  I don't stand steadfast by my numbers however.  I'm just trying to figure out what is reasonable.  What do you think is a reasonable place to start?  Editing my prices to reflect more accurate numbers.  

More feedback on making these accurate.  

Also, I'd like to dig into the discussion of how much value they lose when they aren't NM after the baseline is established.

[Jacob Orlove]

It's not so much that the non-NM ones lose value (they do, but not a ton); it's that the ones that are PSA 9 or 10 (mint and gem mint) are just so rare that they can command ridiculous prices, generally multiples of what the card is normally worth.

[xrizzo]

Honestly, I think these prices are a bit low if you take the best value from ebay.  I can find Alpha/Beta cards from reasonably reputable sellers for 10-15% more than the said prices above...

I would price out like this: (UL, NM/NM- condition)
Ancestral 325
Time Walk 300
Timetwister 210
Sapphire 285
Jet 270
Ruby 260
Emerald 250
Pearl 230
Lotus 450-550  (varies widely)
Bazaar 105
Workshop 140

[jazzykat]

I think prices are more like:

Ancestral 325
Time Walk 290
Timetwister 190-200
Sapphire 300
Jet 270
Ruby 240-250
Emerald 250
Pearl 230

The others I don't really know as I haven't looked lately. Just expect to pay more from well known e bay pimps.

[Tha Gunslinga]

FYI, Jet is pretty much always the #2 Mox, right behind Sapphire.  Here's how I usually price P9 out, based off Ebay, for stuff that's almost NM but not quite PSA-able.

Lotus 600
Recall 325-350
Walk 275-300
Twister 175-200
Sapphire 325-350
Jet 300-325
Ruby 275
Pearl 275
Emerald (I would guess this has a slight edge over Ruby and Pearl) 275
LoA 150