Selling my trading bot license for 0.40 btc, saves you 0.2 btc from buying it outright. Escrow welcome or you send first, buyer pays escrow fee. Once purchased I contact user "Sampey" who makes the bot and have them send current and future updates to your bitcointalk account (trade bot is lifetime membership). PM or post here if interested.
Here is the link to the bot if you haven't seen it before:
https://bitcointalk.org/index.php?topic=507103.0USER gurantee from the creator "However reselling C.A.T. is allowed, and the buyer will receive the same level of support as if they had bought C.A.T. from me personally."