Everything has a value added along the way untill the final owner then often times it will get a value add toward the end of its life again. You can say the same thing about a mecanic. Why should you pay him to fix your car that not right? $350 for a radiator to go in your car? He charges you $200 for the same radiator that you can buy your self for $150 (he has to call and either pick up or wiat for it to be delivered and pay for the item and wait for you to pay as well as deal with making sure its the right part), then charges you an additional $150 to put it in!!! Well that his business, his skill is working on cars, you are paying hium for his knowledge experience time and tools. A guy flipping trailers is spending his time looking to buy and then buying trailers or anything to sell. Even if he did nothing he has time and fuel in it as the OP pointed out. If he thinks he can make money great. Maybe his neighborhood is close to more weathly folks and they pay more for trailers like that, or his area they go for more. We always see on here folks saying that $2500 tractor in your state would be $4000 or more here or that truck would go for $10K here not the $8500 you just paid etc.