To safely and legally tow a 30' AS you'll want a 3/4 or 1 ton truck. Anything less will not have enough tongue weight, not have enough payload, not enough horsepower, not enough brakes, not enough cooling, etc.
Others who should know better will argue (incorrectly) that even a 3/4 ton truck is "overkill" for your 30' trailer.
Others will recommend spending lots of money to jury-rig big chunks of steel onto a poor, helpless minivan.
IMHO these solutions are dangerous for a variety of reasons - especially if you are a first-time tower.
If you are interested in doing the job right you might use this spreadsheet to help guide you. When you start to plug and chug numbers into it you'll quickly start to see that a 3/4 ton truck is not overkill, and that some black magic is involved in making a minivan capable of towing such a large, heavy trailer.
Fuel cost will depend on miles covered and your cost of fuel. Assume that most adequately-sized tow vehicles will get about 10 mpg (US) when towing. You might get lucky and squeak out as many as 12 mpg if you really watch your right foot and keep your speed down.