Exactly! In my France OCC game I could usually get strategic resources for between 200 to 400 gold lump sum. I got luxuries for between 50 to 150 lump sum. The resource is not seen as benefitting you greatly because you only have 1 city; therefore the AI doesn't require as much. It's important to establish trades early on, and keep trading, even if you don't need anything. Keep them Gracious to you (which requires you to be extra generous to them) and I believe they're more likely to give you good trade down the line. Trade, trade, trade.