Original vintage merch is sought after by collectors so you should prepare to pay quite a bit.
My advice, though, is to NOT purchase anything from the rainbowgas seller at Ebay - a stateside shirt collector told that that seller buys old blank deadstock screen stars (etc) 80s brand shirts and prints old school designs on them to make a quick buck, basically bootlegs printed on old shirts to make them look legit.

Cheap boots from Melissa and the EPs do pop up at Ebay regularly so I would rather go for that if I were you._________________A nobody in a world of somebodies
Black market list

The Mercyful Fate this seller has for sale now is identical to mine, which definitely is not a bootleg. You don't just have to print on identical shirts. You have to be a total wizard in order to replicate the colors 100%, which clearly is not the case here._________________Into the Menstrual Night We Go-o, Hey-Ho, Hey-Ho...

He sold a shitload of Slayer - Live Undead shirts which would be easier to replicate due to the colour scheme.
He does also have originals in his shop so this may very well one - it is just that you start to question the legitimacy of the offered shirts when there are some "bad eggs" passed as old originals... I am just saying "be careful".

I will look for the post a shirtchasers and put it up here later if there is interest._________________A nobody in a world of somebodies
Black market list

Let me tell you a little story. Joe Rockwell aka Rainbowgasoline lives just outside of LA. Now, it is no secret that I live in Los Angeles too. I go to a lot of Flea Markets and Swap Meets in the area, hunting for old Metal shirts. The first sunday of every month there is one of the biggest swap meets in the states. It is called the Rose Bowl. It is held at the Rose Bowl stadium in Pasadena. Rainbowgasoline has a booth there as well as 2 other ebay sellers. I will not name them because their shirts are legit and are priced fair. I have heard from a few of the sellers at the rose bowl that Rainbow buys a lot of Blank t-shirts (Screen stars, Jeerzes, Hanes, Sportswear, and anything else from the 80's) from the other vendors. Now why would someone want to but blank stock unless they were going to re-print old style shirts on them to make them look legit. To this day, you can go buy old, blank, screen stars tee's from the NY fashion district and make our shirtchaser shirts on them.

I am not saying that all of his shirts are fake, I am saying that a lot of them are.

That seller also bought new shirts with one account and passed them off as highly overpriced vintage ones with the other._________________A nobody in a world of somebodies
Black market list

I don't know if it constitutes as old, but I have a '97 US tour baseball styled Fate shirt I could be persuaded to part with..._________________Ashes to ashes
Dust to dust
If god won't help me
Then the devil must...