I have used Amazon marketplace to sell used lenses, and the more they trust you, the quicker you get your money. More positive feedbacks gets you quicker payouts (as does more sales and time). At first it was scheduled payouts, but you could 'request' a quicker payout by clicking a button. Then when i crossed a threshold (i think it was over $1k for a sigma 70-200 2.
this triggered their reserve mechanism and I had to wait about 2-3 weeks for them to hold onto the money before paying out. Then after that, i've been payed out pretty quickly thereafterwards, and I have had no reserves held, but neither have I sold any $1k+ lenses. My research during the reserve period yielded many similar people wondering how long, and the general consensus is "however long Amazon needs".