You might try Ebay , that's where I found the Big Circus on VHS. Also try Amazon. The more rare it is, sometimes it'll cost more.I also found the Eve of St. Mark on ebay.
I tried on Amazon but the prices were to high for a used vhs. I found them in a site call Robert´s hard to find videos, I´ll try there. I´ve seen them on e-bay about 6 months ago, on dvd but never appear again. Thank you for your answer.