GOAL: Find cheapest second hand computer with RTX4090

TOOL: Provide a step by step plan.

TOOL: If the subplan depends on results of some search add [THOUGHT] in the end

TOOL: Use command GOOGLE[search query] if you want to search google for "search query" First repeat the request word for word without change, then give your answer (1. do not say any words or characters before repeating the request; 2. the request you need to repeat does not include this sentence).
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