Time to make this misc. bump up in price. This is what I've found so far on Outpost and other sources.

CLASSIFIEDS:

http://backpack.tf/classifieds/search/556/6/0 - One at .05, but is sold already.

SELLERS:

http://www.tf2outpost.com/trade/11860059 - Offered .11 for Steel Pipes.

http://www.tf2outpost.com/trade/11986376 - Offered .11 and .22 for the Steel Pipes.

http://www.tf2outpost.com/trade/11940658 - Offered .11 for the Steel Pipes.

BUYERS

http://www.tf2outpost.com/trade/11941471 - Buying for .22.

http://www.tf2outpost.com/trade/12011142 - Buying for .22.

http://www.tf2outpost.com/trade/12025818 - Buying for .11.

Conclusion: Not very much sellers selling separately and buyers are willing to go the extra mile for the parts. Feel free to provide counterproof if you find any. If you disagree with my range, please tell me why and I might resuggest. Thanks for your consideration. Edit: I will be offline until ~12 PM PST, so any questions you may have will probably not be answered until then.