Sure, you can still get some mexi-brick for $20 a lid (maybe 40-60 these days) but why even bother? As for potency, as horticulture techniques develope, so does the capability of the plant. Since im only 20 years old I have no personal experience with the smoke going around in the 70's, and honestly, im thankful for that. But thats just me. If you're a legal patient, from what I understand you can buy mid-grade bud at the dispensary. If you're not, and you live in NorCal, I would assume it would be fairly difficult to find what you're lookin for on the street. Your best bet would be to ask your supplier to get it for you, but only god knows how awkward that conversation would be. Good luck, and be safe.