Yes. Threads completed in the Bazaar may receive up to 5% of the EXP a character needs to level, but this is awarded entirely at the moderator's discretion. Generally speaking, threads with under 6 posts will not be rewarded any experience, threads with at least 8 posts may be awarded up to 2.5% of the EXP needed to level, and threads with at least 10 posts may receive the full 5%.

Bazaar threads may be submitted for judging if they are in excess of 20 good posts. For such judgings, though, the spoils awarded will only be in the form of EXP and the item purchased; while you may receive significant discounts for such a substantial thread, you will not receive any extra GP for them. Such threads are probably best should you be trying to buy something exceedingly expensive. Indeed, such threads are the only way to purchase the "special" materials that are otherwise unavailable in the Bazaar for normal purchasing.