I've recently traded for about a dozen End of the Line Keys for 15-19 refs (1 normal TF2 key in some cases) from many different sellers. Now, onto the proof... I'm not a regular price suggestion poster, so i will try my best here to supply enough proof to rectify this error.

SOLD:

3 EOTL keys sold for 15 Refs:

http://www.tf2outpost.com/trade/25913869

The same seller with his trade expired waiting for offer at 15 Refs (until i traded for his EOTL keys):

http://www.tf2outpost.com/trade/25495513

Here is the actual deal, not 3 days ago (the trader's 3 EOTL keys for my 45 Refs):

http://i.imgur.com/p0lVgtR.png

More proof (these trades were made from backpack.tf classified listings within the past couple of days):

These trades are from my own: Item Inventory » Inventory History

1 EOTL key sold at 19 refs: http://i.imgur.com/FH65ZY3.png

7 EOTL keys sold at 16 refs each: http://i.imgur.com/6mFB7Ee.png

1 EOTL key sold at 19 refs: http://i.imgur.com/tyYNg0c.png

If the sellers' profiles are required for verification, i can supply these as well. Feel free to ask.

Selling currently for 1 normal TF2 key: http://www.tf2outpost.com/trade/25965052

Edit: Sold for 1 normal TF2 key: http://i.imgur.com/Q5g6fOm.png

UNSOLD:

Since 4 days for 1 key + 2 refs:

http://www.tf2outpost.com/trade/25938999

+ many unsold on bp for above 19 refs.

Based on these sales, it's clear the current suggested price is wrong. I would suggest a price between 15-19 refs. But since a TF2 key is currently fluctuating at about 19 refs, it's easier to set the price to the more stable 1 TF2 key.