It's been a long time since I've seen flights from Chicago to SXM this low for the Feb-March time period. Flights with 1-stop as low as 555 and the Saturday non-stop was listed at just under $600.
The past few years the direct flights have been over $1000 and the flights with one stop usually about $800.
We booked with travel insurance in case anything happens. We did a 8AM flight leaving Chicago and a 5:50 leaving SXM.