Quoted from Rdoyle1978:
It doesnt really depend - almost no sample games bear a higher value than their regular production counterparts. Take TZ, which has a very high number of changes from sample to production. Same value. Even Monster Bash, which had an entire different mech and ramp in the sample - basically the same value. If it’s a super rare thing, where there are only 2 or 3 samples available, you may find more value - but that will be because of the rarity, not specifically because it’s a sample.
Having a sample is just a cool thing to show off to your pinball friends