I have been a courier for way to many yrs. if i had to buy my own van which had to be under 4 yrs old i probaably wouldnt bother working there unless the money was guaranteed to be very very good ( i always buy 5 yr old vehicles and run them into the ground). I can understand needing new cars for passenger carrying but a good clean van 4 or 5 urs old would be more easy on the pocket. failing that hiring or looking at lease with a high mileage limit would be my choice. I worked for a lot of courier companys and there all pretty flexible on the age of vehicles so may be worth asking would they accept a slightly older van.
after paying for the cost of buying your van insurance and then your own diesel then tax insurance them pay checks sure dwindle down in size. so will you earn enough to make it viable?