Better buys can be had in Phillipsburg, if your into fancy french coutre then Marigot, but remember, for every Euro $1.00, it will cost you about $1.21, because of the exchange. My favorite jeweler on St. Maarten is Caribbean Gems, honest and trustworthy, there is a neat market in Marigot, but mostly trinkets, wraps, etc., if you want to by Sarongs, Pareos, etc, here is a secret, ask a taxi to take you to RIMA, it's on pondfill road, they will know where it is, or you can walk about a 20 mintue walk, you can by pareos for 3 for 15, whereas they sell on the beach for 8-10 each!
the butterfly farm is neat, but after about 1 hour, your done, you can walk or hire a taxi to take you to LeGallion Beach, great if you have little kids, (toddlers), no surf, shallow water, and you can rent chairs, umbrellas and they have a small restaurant.
Or have the taxi take you to Orient, my favorite is The Bikini Beach Bar, nice, hardly any nudity, and grea food!!!
We went to St. Marten once on a cruise, and rented a car for the day, its an easy island to get around, but the traffic can be rough, or the best approach, is hire a private taxi for the day, do an island tour with them, then have them bring you back to Town for shopping and then do the beach right there. Look back at my previous post on a St. Maarten trip report, there are 2 links to pictures and some of them are of town and the island
trip report with picture links