how would you check it, how would you change it, how much does one cost....I think that covers my questions

To check it you either need a scan tool to see what your ECM sees, or you need a digital voltmeter and a vacuum pump.

Then you either make sure it is giving reasonable values in the scan tool or put vacuum on it and measure voltage vs. vacuum. 30" vacuum should be ~0V and 5V should be o vacuum.

where is the sensor, if i have a new one would it be easier to just swap it and see if it fixes my problems