DO YOU KNOW how much it costs to go back to school?

Believe me. It's worth it to stay home. Sell your possessions. Make a contribution to Goodwill.

Anything. But don't go back to school. Don't make me finish this story.

Oh . . . all right. But . . . .

If school to you is 1,000 miles away in any direction, find below what getting there will cost you. You may be a fool and plan to travel 1,100 miles to where the cold winds blow and the sun don't shine and where you have 30 credits toward your degree. But for the same money you can be sensible and go south.

This story is going to Miami.

Now there are many ways to get to Miami and the best way by far is in a white Cadillac convertible with the top down doing 80 straight through with the complete works of Carl Orff blasting from the tape player. But the Cadillac hasn't been built that will hold 400 pounds of books, a stereo and four speakers, a refrigerator, 25 pairs of clogs, a king-size waterbed, 12 David Bowie posters, a typewriter, four sets of book shelves, a case of Johnny Walker Red and a sun reflector.

Not in one trip, anyway, and not without a trailer.

Aha! A trailer.

You can rent a trailer and put all that stuff in it and still take the white Cadillac and Carl Orff and whatever and not have cramps when you get there from the picture frame bashing you in the back of the neck all the way through South Carolina.

U-Haul rents trailers, and hitches, for one-way and round-trip excursions. To Miami -- and you are going to Miami -- a one-way trip with a 12-foot trailer, that's a double-axle job (more stability), costs $330. The company gives you six days to get it there and requires a $20 deposit up front. You get the deposit back when you turn the trailer in.

Be sure they can fit your car with a hitch and make reservations early. After this article appears, everybody will be renting U-Hauls and they'll all be going to Miami and U-Haul's prices can change according to "distribution charges." Meaning, if they have too many trailers in one spot they charge the customers to redistribute them.

It's cheaper to make the two-way trip. You may not like it in Miami. Who knows? Or you may have a friend who likes Carl Orff, is willing to ride down with you and will drive the thing back. Especially if it's your Cadillac and you forget the Johnny Walker Red in the car when you move in.

The charge for the same trailer round-trip is $24 a day. But be prepared to shell out a $60-a-day deposit before you leave.

Or a truck. You might have trouble finding a convertible truck. But trucks are also more fun to drive. They normally don't have cruise control and this forces you to stay awake and listen to Carl Orff.

Several companies rent trucks. The prices vary, but none are cheap. Take Ryder, for instance. No, don't take Ryder. Ryder currently has a moratorium (at this writing a week ago) on one-way trucks to Miami because there are too many there already. So take Hertz, for instance.

A 14-foot truck from Hertz rents for $898.40 one-way from Washington, D.C. to Miami. That gives you five days and 1,160 miles, no extra charge. At U-Haul, the 14-footer if $646, plus $30 for insurance and a $50 deposit. U-Haul gives you six days to turn it in, plus 1,225 miles at no extra charge. Each mile in excess costs 25 cents.

Now, you probably won't need your friend if you take the truck unless he wants to help unload and he doesn't mind coming back on the train. At today's gas prices, and with the truck getting only about 5 miles a gallon, the round-trip with a truck becomes high stakes.

Ryder charges $41 a day for a 12-foot truck, plus $7 a day for insurance, plus 18 cents a mile. Figure the trip back and forth takes four days -- approximately 2,200 miles worth of driving. The costs add up to more than $160 for rent, $28 for insurance, $396 for mileage. That's more than $560. The killer is gas, because you will probably spend close to $200 on it each way.

Don't go to school.

Also, don't go to the bank in the truck before you leave. The reason for not going to the bank in the truck is that the top of the truck makes a funny screeching noise when it hits the roof over the drive-in teller machine. The top of the truck rolls back like an accordian because it's not made for hitting roofs over drive-in teller machines and the bank might drop you as a customer which means you have no cash to get to Miami.

Frankly, it makes more sense to take a van, if you can. An eight-passenger van from Avis rents for $33 a day, or $231 a week, and 38 cents a mile. A cargo van from Hertz rents for $30 a day at 17 cents a mile, or $142 a week. A van gets more than 10 miles to the gallon. And no problems at the drivein teller.

Shop around for station wagons. At Hertz the rate is $31 a day and 35 cents a mile. Budget, on the other hand, charges $28.95 a day and 22 cents a mile and throws 100 free miles each day into the deal.

You won't get everything in the truck or the trailer or the car, believe me. You will have books and books and books and all the letters from high school you promised to show your roommate and the Scrabble game and Monopoly and your monogrammed stationery with pictures of Lake Tahoe on it. These you will put in boxes at 2 a.m. the day you are leaving. If you don't read on, you will wrap them with string from your mother's collection in the kitchen drawer and take it to United Parcel Service. They will tell you "no way" because UPS doesn't accept packages with string on them anymore.

Or scotch tape. Or masking tape. You must use HEAVY TAPE. Such as duct tape.

UPS will take up to 50 pounds per box and allows you to send 100 pounds a day to the same address. The box must be no larger than 108 inches in height and girth combined. The charge for a 50-pound box to Miami is $8.90 and is insured automatically for $100.Extra insurance costs 25 cents for each additional $100.

Greyhound and Amtrak are less choosy about what the package looks like. But Amtrak won't take TV sets, stereos, Chevy cans (except by car-rail), or home computers. The charge at Amtrak is $11.60 for each 100 pounds. Greyhound packages express costs $28.95 per 100 pounds and the package must be less than 24-by-24-by-45 inches around

UPS has a home pick-up service. For $2, the truck will drive to your house each day for a week, as long as you call a day in advance of each pick-up.

Be sure to put your address in black magic marker all over the package and be sure to put newspaper inside the bottom of the box to avoid the consequences of Bruske's Law. Bruske's Law states that if there is axle grease or motor oil on the ground anywhere within 500 yards of bus terminal, railroad station or UPS warehouse, the man unloading your box will find it and set your box in it.

And send a post card.