Not cheap, but once you use it you're not going to want to use a cheaper trailer [H] . Also note the resale is REALLY good on these trailers, so you get a large chunk of the $$$ back if/when you sell it.
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Easy to use, tows great (the design keeps the deck height pretty low = low center of gravity AND keeps the car down in the tow vehicle airstream = better mileage), and ideal for lowered cars.
Bought mine "almost new" in 2006, now around 40K miles and counting on it. For what it's worth, the 18 ft one will barely hold my Impala SS (which is also 18 ft long).
Any shorter car easily fits. Charlie's ST 89 Civic Si is pretty much dwarfed on it [:D]