Appropriate sampling frequency for bpsk modulated signal
The sampling frequency depends not only on the carrier frequency and the symbol (baud) rate, but also on the pulse shape. If you transmit with square pulses, you'll need a very large bandwidth (in theory, infinite). If you transmit with sinc pulses, then the base-band bandwidth is half the pulse rate. Other pulses will fall somewhere in between.

To expand on Peter K.'s comment: you should look into using the complex envelope for simulation. The advantage is that, when you use it, the sampling frequency depends only on the symbol rate and pulse shape, not on the carrier frequency.