Tinctures often come in 30ml bottles with a 1ml syringe. Oils are often olive oil or MCT (coconut/palm kernel derived) oil based whereas tinctures are alcohol based. Tinctures are generally absorbed more quickly into the blood stream compared to oils but the effects are the same in the end. Place the tincture underneath your tongue and hold it there for 15 seconds or so then swallow.

THC tinctures and oils alike can get as strong as 30mg per 1ml. CBD and other minor cannabinoids are available in low and high doses (100mg+). Oils tend to be more widely available, though.