I would stick with buying the Casa Fuente line since that is one of the only places you can get them. IMO, the Casa Fuente Lancero ($22) or the Don Carlos Lancero ($18) are the only ones worth paying the premium for. They usually only allow you to purchase 2 Casa lanceros per day, but I've been able to buy more before.

They have rare Forbidden Opus but expect to pay double msrp. BBMF ($125), Destino Al Siglo 13 ($120), Chili Pepper ($75), etc. I've been told they are the same blend as regular Opus just with different packaging.