I found that purchasing the pre-paid Amex Serve cards with cash counts towards the 1,000 dollar status for Gold (even though terms of service state gift cards don't count).
To get Gold for free:
1. Buy 2 Amex Serve cards for 500 dollars (cash) each at Rite Aid, use your Plenti card.
2. Wait 24 hours - you should have Gold status.
3. Spend 1,000 on temporary Amex Serve cards wherever Amex is accepted.