That is definetly part of it. Afterall, I'm flying from Los Angeles to Minneapolis Friday to pick up an '87 and drive it back for exactly that reason. Of course, I'm not even paying half that much for a wagon in similar condition with twice the mileage. Luckily, the owner I'm buying from has all the service/repair receipts dating back to the day it drove off the dealer's lot.

Before looking out of state(CA), I called countless Mercedes dealership service departments and independent shops looking for a lead on '87's. One shop said a guy recently flew out from the Midwest to buy all 4 of their service diesels and take them home to run on discounted agricultural diesel.

But regular diesel is so expensive now that it doesn't make economic sense.

Depends on how many miles you drive a year(regarding vegetable oil). I'm currently spending an average of $260 per month on gas driving a 1991 Honda Accord that gets ~24mpg around for my consulting job. Add in my bi-monthly 800 mile roundtrip winter snowboarding trips and backpacking/camping trips with a girlfriend and two dogs, it's not hard to see why the economics are there in my case. I spend aprox. $4,000+ a year on gas. Running on commerical diesel would save me approx $1,000 from the extra mileage - nice.

But, by running waste vegetable oil(WVO), I'll be giving myself a $3-4k a year aftertax raise without too much extra effort. (I'm already max'd out on reasonable deductions)

[stepping onto soapbox]
Equally important, (cause I'm greenie Californian) I'll be doing my insignificant part to lessen our country's dependence on Middle East oil. Vegie oil/biodiesel certainly isn't the sole answer to our country's fuel problem (there's no single solution), but they are surely one of several, if employed, that can help this country back towards some semblence of energy independence. We just need 20% of drivers to switch from low mileage SUV's/trucks to 24+mpg passenger cars. And the environmental/emission benefits would be massive.
[stepping off soapbox]

And now, back to our regular programming....