What are you guys talking about? If you've played the game long enough to consider buying wonders, you should know that the Stock Market is the best economic first wonder. This is true in 95% of the cases. The only two reasons I think someone might not buy a Stock Market first are:
1. You have the money to purchase a SSS. However, if you have the money currently to purchase it, the question is, why didn't you buy the Stock Market days ago?
2. Someone pays you to buy a wonder. This one I haven't seen as much, but it was just an interesting idea I had thought of if you have someone you trust. I'll probably get shot down on this one by someone on something I forgot, but oh well. Has anyone tried to find a permanent donation seller? Let's say donations are 12m a piece now. If you send them 25mil to buy a FAC and then waste 2 slots a month on donations instead of 4, you might be able to pay the FAC back in a few months. Just an idea that came to my head.
Stock Market is the cheapest "good" wonder and the $10mil lower purchase price helps people start the wonder cycle 2-5 days earlier at the time they start.