Question : Have you considered flying out of an airport besides Sharjah International Airport (SHJ)?
Answer : Departing from Sharjah International Airport is not the only way to get to San Antonio International Airport. Try looking for flights from Dubai Airport (DXB) as well. Over the next two months, flights from DXB to SAT are being booked 81% cheaper than flights from SHJ to SAT. Being only 12 miles away, it's easily accessible for most.
Question : How long do most people stay in San Antonio?
Answer : Of course you're not most people, but if you were, you'd stay roughly 10 days.