Quoted:
Home depot. Black 14ga 500ft spool UV/chemical resistant wire: $40 locally. Buy the 500ft spool and build a bunch of antennae and use it for grounds. I don't see a downside to having 500ft of wire.

Cut 140ft and put it in your go box. Cut yourself a 135ft OCFD for home, then whatever else you need.

MTW (Machine Tool Wire)

http://www.distributorwire.com/blog/index.php/wire-cable-products/machine-tool-wire/

Machine Tool Wire, or most commonly referred to as MTW, is a stranded flexible hook up wire. MTW is used for the internal wiring of appliances including refrigeration equipment, automatic washers, air-conditioning equipment, control wiring for machine tools and in various other building applications.

Although machine tool wire is qualified for many wiring applications it is a simply constructed wire that is made up of a highly stranded bare copper conductor. This high stranding of bare copper gives the wire its superior flexibility compared to that of THHN building wire. The bare copper conductor helps to keep the overall cost of the wire down as opposed to its sister Thermoplastic Equipment Wire, or TEW that is made with tinned copper conductors. The difference of bare copper vs. tinned copper gives the installer the option to choose depending on the application and personal preference of the individual. The tinning is to assist in the soldering process during installation and to help defend against corrosion. The jacket compound on MTW is usually a tough durable Polyvinylchloride (PVC). This compound allows the cable to be heat, moisture, and oil-resistant.

Machine tool wire is available in a wide range of conductor sizes, but most commonly from 26awg all the way larger sizes like 2awg. It is typically rated for use up to 600/1000 volts and for temperatures up to 105 degrees Celsius in a dry location. TEW, is rated up to 105 degrees Celsius in a dry location. MTW is UL listed and CSA listed for TEW or AWM. UL gives MTW/TEW different style numbers from UL1007, UL1015, UL1032, UL1063 and others depending on voltage rating to temperature range.

http://www.wireandsupply.com/product_p/mtw-12g.htm     $0.19/ft  Just not necessary for wire antennas.

http://www.wireandsupply.com/product_p/mtw-14g.htm     $0.16/ft  Good all around for permanent wire antennas.

http://www.wireandsupply.com/product_p/mtw-16g.htm     $0.09/ft  Good for portable wire antennas.

http://www.wireandsupply.com/product_p/mtw-18g.htm     $0.08/ft  Good for portable wire antennas.


THHN

http://www.distributorwire.com/blog/index.php/wire-cable-products/thhn-xhhw/

Building wire is generally used to carry electrical current to all external uses of power in a building or dwelling. This product is utilized in the construction of almost every industrial, residential and commercial building. The most popular type is THHN building wire.

THHN Wire stands for Thermoplastic High Heat-resistant Nylon coated. THHN can come in stranded or solid conductors depending on the size. It is either manufactured in copper or aluminum and covered in a PVC (polyvinyl chloride) insulation with a nylon jacket. THHN is UL listed with a rated 90 degrees Celsius in dry locations or 75 degrees Celsius in wet applications with a THWN rating. The vast majority of THHN building wire carries a dual rating on the cable marked THHN / THWN for both the wet and dry temperature rating. THHN building wire may also be used for wiring of machine tools, control circuits or on certain appliances.

THHN building wire has several main distinctions compared to other building wire products. THHN uses a thinner PVC insulation which is a key factor in terms of its electrical properties. This thinner insulation can often lead to a current leakage and even a breakdown during chemical or environmental exposure. The PVC insulation in THHN also creates a toxic smoke when burned therefore making it undesireable in certain applications.

THHN is not a very flexible product due to its nylon coating. This can often be a factor for many contractors or end users since there is usually a preference to use a product that saves energy and time during installation. However, THHN building wire has grown in popularity since it is a cost effective alternative compared to other types of building wire such as XHHW building wire. Despite some of its down falls, many users of THHN building wire have found this products to be sufficient for meeting their projects specifications.

500' roll of 14 ga stranded insulated THHN at Lowe's or Home Depot is about $45.00 per 500' roll or about  $ 0.09/ft.

Quoted:
I can understand the clad steel vs. copper argument, but what about solid vs stranded?

edit:  posted after the nice big write up!

Quoted:
I'll add that THHN wires clear coating doesn't hold up in the Arizona sun. I put up a commercial OCFD about 2 years ago that uses THHN and most of the clear jacket on the wire is gone. It doesn't affect the antenna tuning though.