You can ask someone closer to look at it for you, and hope they are an expert at what they are looking at, or you can drive/fly/somehow get there to look at it yourself...
Long distance buying is very risky.
The only way to reduce the risk is to become an expert on what you are buying, so you will be able to tell from pictures and description if the reward might
be worth the risk.
Pictures and descriptions can be misleading, intentionally, or otherwise.
If you don't know much about the trailer/car, etc. you are looking at, the risk is probably too great unless you can inspect it in person.
Sometimes a seller will accept a deposit, and usually will honor the agreement, but still, unless I had exchanged several E mails, and spoken with them several times on the phone, I would not drive several states away on a hope and promise.
It would be too easy for them to sell it to someone who walks up with cash, leaving me with nothing but expenses and wasted time.
On the other hand, I may have misunderstood your question...
If you are asking can I buy something long distance on E bay and then decide if I really want it once I see it, that wouldn't be right.
If you simply want to use Pay Pal to send the seller a deposit to hold it until you get there to see it and decide, that would be right.
There still isn't any way I'm aware of though other than getting a feel for the sellers mindset/honesty other than talking with them and just taking a chance that they will honor the agreement, but again, you really need to educate yourself as much as is possible to avoid shafting yourself because you didn't know or understand fully what you were buying or the potential problems it may have that the seller honestly did not know about.