If you are thinking of spending thousands of dollars for a tow vehicle, it would be worth your while to spend thirty dollars or so to get an online subscription to Consumer Reports. They will tell you about the problems the various brands have, and tell you which ones are nearly trouble free.
You will also want to have a look at Trailer Life's towing guide. It will tell you just how much trailer a car or truck is supposed to be able to handle. (Many people, however, think the official figures are too high and prefer to derate them to 75%) You may also be able to get this info, for new cars, from the manufacturers web site.
Generally speaking, little fiberglass trailers can be pulled by a vehicle with a separate frame
(i.e. not a unit-body) and a six cylinder engine
. That would include most trucks and SUVs, but not most cross-overs or mini-vans.
A trailer supply shop, or U-haul
, can outfit you with a hitch. They are available for most popular models with signifigant towing capacity. (I.E. new Dodge Dakota, yes; 1965 Facel-Vega, no.) Trucks can often be ordered with hitches straight from the factory.
In the old days, the best advise was to buy more towing capacity than you thought you needed. Now with fuel costs so high, that might have changed a bit.
Do not expect to get the same high mileage other people say they get. Go with Consumer Reports or even EPA to estimate that.